The MonthlyJ ournal ofthe INSTITUTE OF METALS

M i m *? . I o cu

papers 7 0 9 —711 to be printed in the half-yearly volume :

Journal o f the Institu te o f Metals, 1935, Vol. LVII.

Vol. 2. Part 7.

The Monthly Journal ofthe

INSTITUTE OF METALS

and|P 0 LntC \ ’K j

METALLLRCICAL ABSTRACTS

JULY, 1935

"opyright][Entered a t Stationers’ H all

ONFERROUS AUOYSare unecjuallsd(or

CONSISTENT OUALITYand are produced in

NOTCHED BARS, INGOTS, ROLLING SLABS, WIRE BARS, STICKS and SHOT

to

ADMIRALTY, A .I.D ., B.E.S.A. and all Standard Specifications

Particular attention is drawn to our

STANDARDIZED ALUMINIUM ALLOYS for

SAND-CASTINGS, GRAVITY and PRESSURE

DIE-CASTINGS and SPECIAL HIGH-TENSILE

ALLOYS for AIRCRAFT and ADMIRALTY W ORK

CONT R AC TO RS ro TM £ ADMIRALTY AN D PM NCl PAL &, A I t 'vVA Y COM P A Ml £ SWONE.YICTOUA J581-2-S GB.AMS.SPECIFlC MH.MINGHAM

P r . n t b d .N G r h a t B r , t a , n By R . c h a r d C l a y a n d S o n s , L t d . , B u n g a y , S d f p o l k .

h 0 ^ e tof ei p e f r * c

* g

Fro m o u r w ide r a n g ę w e a re a b le to su p p ly r e f r a c to ry m a t - e r ia ls o f h ig h q u a li ty su i ta b le fo r m o s t in d u s tr ia l purposes. In o u r v a r io u s works, w hich a r e m o d e r n in d e s i g n a n d e q u ip m e n t , c a r e is t a k e n in every s t a g e o f m a n u f a c tu r e to e n s u re t h a t o u r p ro d u c ts a r e m a i n t a i n e d a t a u n i f o r m l y

h ig h s t a n d a rd .

For fu lle r particulars, ask fo r our Pam phlet, No. 1.

SCOTLAND

The illustration shows blade blanks before

machining.

“ Flight ” Photo.

^BRITISH ALUMINIUMH eadO ffice :ADELAIDE HOUSE. KING W ILLIAM STREET, L0 ND0 N,e.c.4Telephońe: MANSION HOUSE 5561 &8074(5UNES).7<e/egro/ns;CRYOLITE,BILGATE,LONDON

LO N D O N W AREHO USE: 25-29, Pancras Rd., N .W .I . BIRM INGHAM 4 : Lawley St.MANCHESTER: Deansgate House, 274, Deansgate. LEEDS 3 : 66, K irksta ll Rd.NEW CASTLE-O N-TYNE I : M ilburn House. G LASG O W C .2: 113, W est Regent St.

JiM -7.35

i i i A

GENERAL I N D E XTO

TH E J O U R N A LA N D

M E T A L L U R G I C A L ABSTRACTS

VoIs. 26 (1921) to 55 (1934)

Members are requested to o rder th e ir copies

of the above at an early date, as the publication

of this lndex can only be proceeded w ith if a

sufficient num ber of orders are secured in

advance.

The lndex w ill consist of Tw o Volumes— Names

and Subjects— and is expected to contain 1100

pages, closely printed in double column.

ADVANCE SUBSCRIPTION PRICE

Two Volumes: Names and Subjects 25s. post freeO neYolum e: Names or Subjects I5s. „ „

N O T E : If sufficient orders are secured it is hoped to publish the Names lndex at the end o f the present year.

»

. V

p ta łd ks*

BRASS, COPPER CUPRO-NICKEL A L U M I N I U M —

BRASS

WE also make Sheet and Strip in Brass, Copper, Bronze and Nickel Silver, etc., Extruded Rods and Sections, and also “ DURALUMIN ” of which we are

the sole makers.

J a m C S U sCLiiparaj iintitedA.RGYLE STREET WRKS, BIRMINGHAM,7.

Telephone: EAST 1221 (P.B.E.). Telegam s: “ Booth, Birmingham.”

Cables: Lieber’s 5 le tter. A .B.C. 6th Edition. B en tle /’s Second Phrase. W estern Union.

INDIAN ORDNANCE FACTORIEST he Secretary of State for India invites applications for the post o f Assistant

Works M anager a t the M etal and Steel Factory, Ishapore, Bengal. Salary, Rs. 600 a m onth plus £25 a m onth sterling overseas pay, rising by annual incre- m ents o f Rs. 50 a m onth to Rs. 800 a m onth plus £ 25. T he appointm ent is non- pensionable, bu t there is a Provident Fund, subscription to which is compulsory. Free passage to Ind ia is g ra n te d ; and ąuarters, if available, are provided a t a rental no t exceeding 10% o f salary. An Agreem ent for five years will be entered into in the first instance.

Candidates m ust be British subjects and the sons o f British subjects. They m ust be well educated and should be between the ages o f 25 and 35 years. They should have obtained a University degree or its equivalent, preferably in m etallurgy, and should have had a t least five years’ experience w ith a firm of repute dealing with melting, casting, hot- and cold-working (rolling and drawing) and heat-treatm ent o f non-ferrous metals. Experience in press work, extrusion, and particularly ofE lectric Furnace m elting o f non-ferrous metals, will be an advantage. Candidates should have good ideas o f shop organization and be able to control subordinate staff and labour.

T he selected officer will be reąuired to proceed to Ind ia about the middle of Septem ber next.

Applications should be subm itted as soon as possible before the 3 ist Ju ly , on forms to be obtained from T he Secretary, M ilitary D epartm ent, Ind ia Office, London, S.W. 1 . Envelopes should be m arked O rdnance (Ishapore) R ecru itm ent.”

Applications from candidates w ho do not possess the reąuisite ąualifications cannot be considered.

India Office, June, 1935 .

¥ OXYGEN “1Masterof Metals

The first Ozy-acetylene rod to be approved by Lloyd's for u clding parts o f p n m a ry structural importance in shipbuilding.

‘ Aida ’ S.M. No. 1 Rods for the oxy- acetylene welding of Steel for all purposes where high tensile strength is reąuiredS U P P L IE D IN 36" L E N G T H S IN T H E FO LLO W IN G D IA M ETERS:

1 " 5 " 3 " 7 " 1 "8 . 32 , T6 i 32 , 4

THE BRITISH OXYGEN CO., LTD.,• -N Victoria Station H ouse, W estm inster, S.W. 1

• • • • • . 41 B.O.C. Oxygen and D .A . Works• : ^ : . *n Gt. B n ta in and N . Ireland and 23"

tn Australia, South A frica and India .w . .. w?/® . o : ■ ; i;-;; o :

Incandescent Furnacesfor all Heat-Treatment Purposes andforall

Industries

Above is a Battery of Patent IncandescentTwin- Chambered, Coal-Fired Furnaces installed fo r the heat-treatment o f the crankshafts of various well-known m otor cars.

We supply Furnaces for all Industries, Coal, Cokfi, Tow ns Gas, Producer Gas, O il and Electrically Fired

also

PY R O M E TR ICE Q U IP M E N T

Separate Brochure fo r every Industry

Your enguiries are invited.

INCANDESCENTMAT COMPANY IIMHIDCORNWAIL ROAD SHETHWICK

i B I R M I N G H A M '■Telephone: Smethwick 0875-7. Telegrams: * Repeat,’ Birmingham.

v i i

POLISHED and PLATED SHEET M ETALSZIN C , T IN PLATES, NICKEL SILVER, BRASS, ETC.

Plated with CHROMIUM, NICKEL, BRASS, COPPER

P/ease s e n d u s y o u r

e n g u ir ie s :

Sheets up to 84 by 18 in.Strips 84 in. by any width. Any gauge.

W . E. MARTIN & CO. LTD.HOCKLEY

Telephone: N o rth e rn 296I-2.

MANUFACTURERS BIRM ING HAM , 19Telegram s: BEEZEDD, B’HAM .

FOUNDRY SERYICES, LTD.

LONG ACRE, NECHELLS,

BIRMINGHAM, 7

v i i i

For the economical production of tubes with absolutely uniform wali thickness we supply

T U B E E X T R U S I O NPRESSES

of vertical or horizontal type, also the required power w ater plants consisting of pressure pumps and accumulators, the latter of the electrically controlled, com- pressed-air loaded type w ithout any pistons

or floats, for which the H Y D R A U LIK Co. owns patents in all countries of the world.

British Agents: Aabacas Engineering Co., Ltd., 10 Canning Place, Liverpool, Ii x

a new service to members

Members who find it inconvenient to bring to the General Meetings copies of the Monthly Journal containing the papers to be discussed, may now purchase one loose copy of each paper. Orders, which must be for one whole year in advance, should be sent to the Secretary without delay. The service will commence with the Autumn Meeting, 1935, papers.

Annual charge 5s., post free.

metallurgical®§2 lIS ) MICROSCOPE “A”for the Labora to ry and

WorkshopThis instrument is capable of numerous adaptations for the inspection of metals and other opaque substances.

The body can be rotated o r displaced vertically upon a stoutvertical column.and is secured by means of a clamp.

The vertical illuminator incor- poratesa built-in electric illuminating device: a valuable aid to rapid focusing.

A variety of stages can be fitte d , both above and below the foot, to facilitate the examination of smali or large objects.

F u l i parłicu la rs i n lis t “ W in k e l 1 4 1 ”

CARL ZEISS (London) Ltd.Mortimer House, Mortimer St.

LO N D O N , w . i

X

h i d u m i n i u m

m Ę tk

HIGH DUTY ALLOYS Eo u c « *

(i+ł 82 2 Grarm: ALLOYS, SLOUGłł

APERIODIC & MICRO- CHEMICAL BALANCES

Please w rite for N ew List showing Instruments of the most ad- vanced design.

British Made by

L. OERTLING LTD.65 HOLBORN YIADUCT, LONDON, E.C.1

Founded in London 1849.

TAS/Or. n 6

VITREOSIL

MUFFLES

THE

TH E R M A L S Y N D IC A T E LT?VITREOSIL WORKS

W A L L S E N D -O N -T Y N E

London D e p o t:

Thermal House, O ld Pye Street, S .W . I

VITREOSIL, pure fused silica, withstands heat up to II00°C . and is unaffected over long p e r i o d s . I t is t h e r e f o r e eminently suitable fo r muffles used fo r all metallurgical purposes, heat-treatment, labora- to ry testing, etc. C ircular muffles as illustrated are made up to 10 ft. in length ; other shapes and sizes are obtainable.

STERLING METALS LTD

COVEN^RYió35 r n V F K I T R V S T E ^ T h O N E(3 lines) I ^ * Coventry.

Alum inium Die Cast Heavy Brake Shoe

DIE CASTINGSNormal or hear Ireated

SIEM

ENS-

SCH

UCK

ERT

x ii i

Siem

ens

- Sc

huck

ert

(Gre

at

Brita

in)

Lim

ited

30/34

Ne

w Br

idge

St

reet

, E.

C.4.

T

el.:

Cent

84

61.

INDEX TO ADYERTISERS

Anglo-American Oil Co., L td . . Avery, L td., W. & T.Birmingham Electric Fum aces, L td. Bolton & Sons, L td ., Thomas . Booth & Go. (1915), L td ., Jam es British Aluminium Co., L td ., The B ritish Commercial Gas Assoc., The British Metal Corporation, L td

The .B ritish Oxygen Co., L td ., The Brookes (Oldbury), L td . . Carborundum Co., L td ., The Consolidated Tin Sm elters, L td Demag A.G.Eboneatos Insulators, L td .Electric Resistance Pum ace Co. Electroflo Meters Co., L td .E lliott Bros. (London), L td.E lton, Levy & Co., L td . .Fordath Engineering Co., L td.Foster Instrum ent Co.Foundry Services, L td .General Electric Co., L td.H igh-Duty Alloys, L td . .

L td

J U L Y , 1 9 3 5PAGE

— Hilger, L td ., Adam— H ydraulik G.m .b.H.— I.C .I. Metals, L td . .— Incandescent H eat Co., L td .v Johnson, M atthey & Co., L td . .

iii Leitz (London), E . .— McGraw-Hill Publishing Co., L td.

McKechnie Bros., L td.xix M artin, W. E . & Co., L td.

vi Metropolitan-Vickers, L td .— Murex, L td . . . . .

cviii National Alloys, L td.— N orthern Aluminium Co., L td . .— Oertling, L td ., L.— Pearson, L td ., E . J . & J . .— Priestm an, L td., T. J .— Ratclifi (Metals) L td ., J . F.— Siemens-Schuckert (Gt. Britain) L td .— Stein & Co., L td ., John G.— Sterling Metals, L td .—- Stew arts and Lloyds, L td .

viii Therm al Syndicate, L td . .— W ild-Barfield Electric Furnaces, Ltcxi Zeiss (London), L td ., Carl

PAGE

ix

VIIxvi

X IXviii

X Xxivxiii

iixii

xiiX V

is a matter of comparisonand it matters very much, when you are buying rolled metal, what standard you use to make your comparison.

If you have seen LUSTER Metal produced ; followed the process from start to finish, watched the pationt testing of raw materials, admired the modern electric annealing process, noted the almost meticulous care taken in each stage of manufacture, you will be con- vinced that here is your standard for Rolled Metal . . . LUSTER.

T h e p h o to g r a p h sh o w s som e finished rolls and strips waiting delivery instruction=.

J. F. RATCLIFF (METALS) LTD., NEW SUMMER STREET, BIRMINGHAM

Quality

Telephone: Aston Cross 3576/7. Telegrams: “ Rodenc, B irm ingham ."

x i v

S P E C I A L F U R N A C E STO SUIT SPECIAL REQUIREMENTS

The i l l u s t r a t i o n shows a r o t a r y drum type non- ferrous annealing furnace fo r continuous annealing o f smal i c o m- ponents. This is only one example of the numerous special equipments designed and made to suit particular r e q u i r e m e n t s .

YILD-BARFIELD ELECTRIC FURNACEST D ‘ ' E L E C F U R N W O R K S - N O R T H R O A D - H O L L O W A Y - L O N D O N - N .7

B R A Z I N G A L L O Y W * * # * *

Flows freely at 1,3 0 0 ° F. (705° C .). Penetrates quickly and thoroughly. Requires less flux. W o rks fast. Is

easy and economical to use. Makes

strong joints which resist vibration.

•

For Brazing Copper, Brass, Bronze, “ D elta” Metals and other non-ferrous Alloys which meltabove 1,300°F. (705°C.).

•

Under a wide variety of conditions, Sil-fos joints are strong and ductile. Laboratory tests on Copper-to-copper lap joints made without using flux have shown an average tensile strength of 33,000 pounds per square inch, with an elongation of

17*2% in 2 inches.

W rite fo r Booklet No. 90

lohnSon\fetthey&/o |td

73/83, HATTON GARDEN, LO N DO N, E.C.I. 71/73, VITTORIA STREET, BIRMINGHAM, I.

38, BATH STREET, GLASGOW, C.2.

x v i

E ditorial Office : 36 Victoria Street,

London, S.W .l.

Telephone :Yictoria 2320.

T H E

Monthly Journal of the

IN S T IT U T E O F M E T A L S

Ad?ertising Department :

T. G-. Scott & Son, Ltd.

63 Ludgate Hill, London, E.C.4.

Telephone :C ity 4211 (2 lines). Assistant Editor:

S. O. GUILLAN.

Y o lu m e JU L Y , 1935 P a rt 7

CONTENTSInstitute News and AnnouncementsLetter to the E d i t o r ..........................................

PAGE

. 341. 342

By

Papers to be Read at the Autumn Meeting :7 0 9 . "T h e Protection of Magnesium Alloys Against Corrosion.’'

H . Sutton, M .Sc., and L . F . Le Brocq, B .Sc................................................. 343

7 1 0 . “ Electron Diffraction Examination of Protective Films Depositedon Magnesium and Magnesium Alloys by the R.A.E. Dichromate Process." By H . G. Hopkins, A.R.C.S., B .Sc..............................................365

7 11 . "Alloys of Magnesium. Part III.—Constitution of the Magnesium-Rich Alloys Containing Aluminium and Cadmium.” By J. L . Haughton, D .Sc., and R. J. M . Payne, B .Sc........................................................................ 369

Author Index to “ Metallurgical Abstracts ” ..................................................... 382

I .II.

I I I .

IV . V .

V I.V II.

V III .IX .

X .X I.

X I I .X I I I .X IV .

XV.X V I.

X V II.X V III .

X IX .X X .

X X I.X X II .

X X II I .X X IV .

M ETA LLU R G IC A L A B S T R A C T SP roperties of M etals . . . . . .P roperties of A lloys . . . . . .S tru c tu re (M etallography; M acrography; C rysta l S tru

tu r 0) . . . . . . . .Corrosion . . . . . . . .P ro tection (o ther th a n E lectrodeposition) E lectrodeposition . . . . . . .E leetrom etallu rgy an d E lectrochem istry (o ther th an E lectr ■

deposition) . . . . . . .Reflning . . . . . . .A nalysis . . . . . . . .L ab o ra to ry A p p aratu s, In s tru m en ts , & c..P hysical an d M echanical Testing, Inspection , an d Radiolog T em pera tu re M easurem ent an d Control .F o u n d ry P rae tice a n d A ppliances . . . .Secondary M etals : Scrap, Residues, &c.Furnaces and Fuels . . . . . .R efractories an d F u rn ace M aterials H eat-T rea tm en t . . . . . . .W orking . . . . . . . .Cleaning an d Fin ishing . . . . . .Jo in ing . . . . . . . .In d u s tr ia l Uses an d A pplications . . . .M iscellaneous . . . . . . .B ib liography . . . . . . .B ook Review s . . . . .

333336

342345348349

351

352 354 354 357357

358359

360 360 362

T he m on th ly issue of M etallurgical Abstracts m ay be c u t up for card indexes as m em bers will receive early in 1936 th e y e a r’s ab s trac ts in bound form .

Carborundum Brand Refractories

For Clinker Proof Linings of Boilec Furnaces.

Carbofrax Brick.Carbofrax - Bernitz air-

cooled Blocks.

For Melting Non - Ferrous Metals.

C arborundum Crucibles.

For the Lining of Non-ferrous Melting Furnaces.

Carbofrax Brick.Carbofrax Cements. C arborundum Firesand.

For Settingof Brick and Tile. Carbofrax Cement.A cement to meet every

condition.For Enamelling Furnaces. Carbofrax Muffles.

For Potteries.The Carbo - Radiant Oil-

Fired Kiln.

For greater Efficiency from Heat Treating Furnaces.

Carbofrax H earth Tiles.

For Recovery of Waste Heat. The C arbofrax Recuperator.

In other words, a Carborundum Brand Refractory for practically every High Temperature Installation.

We are prepared to advise customers on matters of furnace design relative to the use of Carborundum Brand Refractory Products, or will undertake to design and build complete Furnace Installations.

The Carborundum Company Ltd.,Trafford Park Manchester.

x v ii i

I N S T I T U T E N E W S A N D A N N O U N C E M E N T SĘL

Autumn Meeting, Newcastle-upon Tyne, September 9-12.

% T h e finał program m e of th e New-* castle-upon-T yne M eeting should be

r in th e han d s of all m em bers sho rtly/ a f te r th e receip t of th e p resen t issue* of th e M onthly J o u rn a l; an ou tline of

th e p rogram m e appeared in o u r last issue. W ith th e finał program m e will be found a reply form th a t should be re tu rn e d to th e Secretary , n o t la te r th a n A u g u st 16, b y all m em bers who in ten d to tak e p a r t in th e m eeting. I f an y m em ber does n o t receive a copy of th e p rogram m e an d reply form , application fo r a dup licate of each should be m ade to th e Secretary .

H o te l accom m odation in Newcastle is som ew hat lim ite d ; m em bers should m ake reservations, therefore, d irectly w ith th e hotels as early as possible. A list of th e chief hotels w ill be found in th e m eeting program m e. I t is hoped, how ever, th a t as m an y m em bers as possible will app ly fo r accom m odation a t th e U niversity H ostel, w hich has k indly been m ade available b y th e U niversity au th o ritie s fo r th e use of m em bers a tten d in g th e N ew castle m eeting. The P residen t and o th e r M em bers of Council have a lready ind icated th e ir in ten tio n to s tay a t th e H ostel.

The charge fo r accom m odation, inclusive of g ra tu ity , will be l i s . pe r d a y ; th is su m covers b a th , bed, and b reak fast, also d inner w hen required . No luncheons will be served ; these will be ob tainab le in th e U niversity U nion a t 2s. each. A ccom m odation can be prov ided a t th e H ostel for 80 persońs— m em bers an d ladies. The H ostel is m odern , very com fort- able, an d is licensed. I t is w ith in easy reach of th e c ity b y tra m , an d offers garage accom m odation for 14 cars.

B y stay ing a t th e H ostel m em bers will find th a t o p p o rtu n ity fo r social in te rcourse w hich is so valuable a fea tu re of th e A u tu m n Meetings. M em bers a re , therefore, strorigly recom m ended to m ake use of th e H oste l facilities.

The necessary accom m odation shoud be reserved d irec t by le tte r addressed to : The local H onorary Secretary , Mr. C. E . Pearson, M .Met., A rm strong College, Newcastle-upon- Tyne.

Y

Visitors from Overseas.Several v isitors from overseas have

called a t th e offices of th e In s t i tu te d u rin g th e p as t m onth , these including Mr. W . M. Corse (Corresponding M em ber to th e Council for th e U nited S ta tes of Am erica), P rofessor G. O rland (Liege, B elgium ), Mr. E . G. T h u rlb y (M elbourne, A ustra lia), and Mr. E d m u n d M. W ise (Bayonne, N. J . , U .S.A.). Overseas M em bers visiting L ondon a re invited to m ake fuli use of th e In s t i tu te ’s L ib ra ry , R eading Room , a n d o th e r facilities.

Annual Subscriptions.M any m em bers have a lready been

good enough to rem it th e ir su b scrip tions for th e new financial year, w hich com m enced on Ju ly 1, w ith o u t receiving th e u sua l subscrip tion ‘e rem inder. ’ ’ T he subscrip tions of over 550 o ther m em bers w ere pa id on Ju ly 1 by m eans of B an k er’s O rders; in th is w ay a v e ry considerable saving of lab o u r an d expense has been effected. J t is th e hope of th e Council th a t still m ore m em bers will tak e advan tage of th is convenient m ethod of paym ent. All th a t th e m em ber has to do is to fili in a form , to be ob tained from th e Secretary , in stru c tin g h is banker to p ay his su b scrip tion to th e In - s t i tu te ’s b an k er every year. This saves th e m em ber w riting of cheąues, s tam p d u ty on cheąues, addressing envelopes, an d postage, and it saves th e In s t i tu te th e p rep ara tio n of receip ts, addressing envelopes, and postage, for, as th e m oney passes d irec t from one b ank to ano ther, no receip t is necessary. I t also obviates th e need, in certa in case3, fo r issuing several notices regarding subscrip tion arrears.

To those m em bers whose su b scrip tions h ad n o t been paid by th e date due, J u ly 1, th e re have a lready been sen t le tters from th e Secretary remind- ing th em th a t th e a m o u n t payable for th e y ear 1935-1936 is £3 3s. in the case of O rd inary M em bers o r £1 1 .9. in th e case of S tu d en t Members. m a n y

P O U N D S W IL L B E S A V E D T O T H E IN S T IT U T E I N S E N D IN G F U R T H E R R E - M IN D E R S I F M E M B E R S W H O H A V E N O T Y E T P A ID T H E IR S U B S C R IP T IO N S W IL L B E G O OD E N O U G H TO F O R W A R D T H E M W IT H O U T D E L A Y .

Letter to the EditorPersonal Notes.

Me . Alan L . B b a d l e t h a d con- ferred upon h im a n A ssocia tesh ip in M etallurgy (N on-Ferrous) a t a Degree C ongregation of Sheffield U n iversity , held on Ju n e 29. H e h as also been aw arded th e N esth ill M edal an d Prem ium .

Sir H e n e y F o w ie e , K .B .E ., L L .D ., D.Sc. (P ast-P re sid en t), has h ad a n o th e r slig h t b reakdow n in h ea lth a n d will be obliged to re s t for som e weeks.

Sik R obebt H a d eield , B a rt., F .R .S ., h as been aw arded th e A lbert M edal of th e R oyal Society of A rts “ fo r his serviees in m eta llu rg y and his services to th e steel in d u s try .” The A lbert M edal is given an nually “ fo r d istingu ished m erit in pro- m oting A rts , M anufactures, o r Com m erce.”

Death.M o n sie tjk A n ijkk C i tk o e n died

on J u ly 3, in P a ris , a t th e age o f 51. H e w as P re s id e n t o f th e Conseil d ’A d m in is tra tio n de la Societe A nonym e des A utom obiles C itroens, a n d h a d been a m em ber o f th e In s titu te sińce 1928.

British Foundry School.A p ro sp ec tu s has been issued b y th e

G overning B ody of th e B ritish F o u n d ry School, w hich h as been estab lished fo r th e p u rp o se of th e fu r th e r tra in in g of m en w ho w ish to ąu alify fo r positions of th e h ighest responsib ility in th e fo u n d ry in d u s try o r who have a lread y aehieved such positions a n d who w ish to ex ten d th e ir m etallu rg ical an d technical knowledge to m eet th e v e ry considerable ad- vances th a t have been m ade d u rin g th e p a s t few years.

T he school fo rm s p a r t of th e na tio n a l schem e of fo u n d ry ed ucation estab lished largely on th e in itia tiv e of th e In s t i tu te of B ritish F o u n d ry m en an d th e B ritish C ast-Iron R esearch A ssociation. The school is th e only one of i ts k in d th a t has na tional

s ta tu s . I t is su p p o rte d b y th e B oard of E d u ca tio n an d a large n u m b er of scientific a n d techn ica l bodies. T h rough th e pub lic -sp irited action of th e B irm ingham E d u ca tio n C om m itte it has been possible to house th e school in th e w ell-equipped M eta llu rgical D e p a rtm en t of th e B irm ingham C entra l T echnical College, from th e P rin c ip a l of w hich college, o r from th e H o n o ra ry A dvisor to th e G overning B ody, M r. J . Cr. Pearce , 21 S t. P a u l’s Sąuare , B irm ingham 3, th e re can be o b tained copies of th e p rosp ec tu s of th e B ritish F o u n d ry School.

L E T T E R T O T H E E D I T O R

Effect of Cold-Working on Density.I t w as show n in 1861 b y C. 0 ’Neill

of M anchester th a t severe cold-working of copper p roduces a slight b u t definite decrease of density . D r. C. F . E lam in h e r book en titled “ The D isto rtio n of M etal C rysta ls ” cor- rec tly re p o rts (p. 137) th a t th e p re se n t w rite r (J . Iro n Steel In s t., 1924, 109, 93) confirm ed th e sam e effect fo r an aggregate of iron. She goes on to say, how ever, th a t sim ilar m easurem ents m ade b y m e on a single c ry s ta l of silicon-iron show ed no significant change of density , an d ingenuously a d d s : “ . . . b u t th is re su lt isd o u b tfu l.”

I am n o t aw are of th e a u th o r’ś experim en tal w o rk (if any ) on w hich th is d o u b t is based, b u t s tu d e n ts of th e su b je c t who a re inclined to share he r m isgivings should pe rh ap s be inform ed of tw o pieces of evidence n o t c ited in th e book. D r. Pfeil (Carnegie Schol. M em ., Iron Steel In s t . , 1926, 15, 319) h as fu lly confirm ed m y findings for single c ry sta ls of p u re iron , a n d D r. H . G ough (see C an to r L ectu res, 1928, p . 103) h as show n th a t th e sam e re su lt holds t ru e fo r single c ry sta ls of alum in ium .

H u gh 0 ’N e il l .D erby .

342

PAPER No. 709. This paper is copyright. It, m ay be reprinted, wholiy or in p a rt in the T w t + due acknowledgment) a fte r being presented a t the A utum n Meeting of the In s titu te to be held on September 9-12, 1935, in Newcastle-upon-Tyne. The Institu te as a body is n o t responsible fo r the statem ents or opinions expressed in th is paper on which wntten discussion m ay be sent to the Secretary no t la te r than October 1, 1935.

THE PROTECTION OF MAGNESIUM ALLOYS AGAINST CORROSION.*

By H . SUTTON.f M.Sc., M e m b e r , and L. F . Le BROCQ,J B.Sc.

S y n o p s is .

Shąrt-tim e chrom ate treatm ents of magnesium-rich alloys of two types in oommon use have been investigated, and the protective value of the treatm ents has been compared w ith the 6-hr. chromate treatm ent and o ther forms of protective treatm ent.

A bath has been evolved capable of giving good films in 30-45 m inutes, and which is suitable for use in Steel'or aluminium tanks.

The proteetiye value of the 6-hr. and short-tim e chromate treatm ents, w ith and w ithout supplem entary coatings of yarnishes and enamels, has been investigated w ith reference to typical alloys. In term itten t sea- w ater spray laboratory tests and beach exposure tests were carried out, and the corrosion which occurred was observed by loss of weight and change in m echanical properties.

Experim ents were carried ou t on the influence of cleaning treatm ents employed before chromate treatm ent.

I n a previous paper 1 the present authors described experiments which showed th a t substantial protection of magnesium-rich alloys could be obtained by surface films produced by immersion of the cleaned pieces of the alloy for about 6 hrs. in a bath (Bath 2) containing potassium dichromate 1-5, potash alum 1, and caustic soda 0-5 per cent., heated to 95° C. The benefit obtainable by protective films produced by simple immersion treatments on magnesium-rich alloys was further investigated by Bengough and W hitby.2- 3

Sh o r t -T im e Ch r o m a t e T r e a t m e n t .

Of the chromate treatm ents which had showed most promise, Bath 2 treatm ent has been found for some purposes inconvenient, on account of the lengthy period reąuired by the treatment. Treat- ment in a bath containing potassium dichromate 1-5 and sodium sulphate decahydrate 1-5 per cent. a t 100° C. for 30 minutes gave approximately

* M anuscript receiyed May 10, 1935.4 - f Sęientific Officer and Head of the Metallurgical Departm ent, RoyalAircraft Establishm ent, South Farnborough.

t Scientific Officer, Royal Aircraft Establishm ent, South Farnborough.

Notę to Abstractors and Other Readers.—This paper will be published, in perm anent form, in the Journal of the Institute of Metals, Vol LV II 1935 Reference should accordingly be as follow s: J . In st. Metals, 1935, 57 (Adyance

709

34 3

Sutton and Le Brocą: The Protection of

equal protection, but the bath was found to suffer loss of ac tm ty rather too ąuickly for generał convenience of working. Experiments have now been carried out with the object of evolving a short-period immersion treatm ent, and it has been found th a t treatm ent for 45 minutes in a bath (Bath 2B) containing :

Potassium dichromate, weight per cent. . . . 0-75Ammonium dichromate, weight per cent. . . . 0-65Ammonium sulphate, weight per cent. . . . 3-0Ammonia (0-880), per cent. by volume . . . 0-33

and used a t boiling point gives a degree of protection very little inferior to th a t afforded by Bath 2 treatm ent. The bath was found to be capable of repeated use without loss of efficiency. During use of the bath the value remains nearly constant a t about 6-5, and the reason for this appears to be th a t as magnesium is dissolved from the work under treatm ent, ammonia is liberated from the ammonium salts present and escapes from the boiling solution. Other baths which appear to give good films are a chromate magnesium sulphate bath (Bath 4) and a phosphate bath (Bath 5).

Samples 4 in. long X f in. wide of 14G sheet materiał of composition corresponding to Air Ministry Specification D.T.D. 120 and of sheet in the manganese-magnesium alloy to Specification D.T.D. 118 were prepared for corrosion tests of the interm ittent sea-water spray type.4 In these experiments losses due to corrosion were estimated by weighing the test-pieces before exposure, removing corrosion products after exposure by washing the specimens thoroughly, soaking in cold 5 per cent. caustic soda solution for 24 hrs., and im- mersing them for 1 hr. in boiling 5 per cent. solution of potassium bichromate solution and re-weighing.5 This method for removing the corrosion products has the advantage th a t the amount of metal removed is insignificant and also th a t any of the original protective films remaining after exposure are not removed from the specimens. Magnesium alloys sufier practically no loss in weight by immersion in this solution provided th a t chlorides do not accumulate during use to a greater extent than 10 per cent. of the content of potassium dichromate.

The results obtained are given in Table I, the loss of metal due to corrosion being expressed in grm./dm.2 of surface. The results indicate that, for specimens not subseąuently painted or greased, Bath 2 trea tment gives the best protection in the conditions of the tests, but tha t treatm ent in Bath 2B affords almost equally good protection of alloy

344

D.T.D. 120, whilst both processes are still more effective on alloy D.T.D. 118. In view of the attractive appearance of the films the results on samples treated in the phosphate bath were very disappointing. The compositions of the various treatm ent baths and details of the treatments are given in Table XVI.

Magnesium Alloys Against Corrosion

T a b l e I .— Results of Intermittent Sea-Water Spray Corrosion Tests on Samples Treated by Short-Time Processes (S ix Weeks’ Exposure).

Treatment.

Alloy D.T.D. 120. Alloy D.T.D. 118.

(Al 6-7, Zn 1-02, Mn 0-24, Fe 0-06 Si 0*01%, rest Mg.) (Mn 2-5, Al 0-1% rest Mg.)

Loss, Grrm./dm.2. Mean. Loss, Grm./dm.s. Mean.

B ath 4 1-8 0-292-5 2-4 0-42 0-372-8 0-39

B ath 2B 1-7 0-182-4 2-0 0-12 0-181-8 0-25

B ath 5 2-6 2-53-6 3-0 3-6 2-82-8 2-2

B ath 2 1-5 0-021-6 1-7 0-02 0-0172-0 0-01

P r o t e c t io n o f M a g n e s iu m A l l o y Ca s t in g s .

The suitability of these methods of protection when applied to sand-oast blocks of magnesium alloy to Air Ministry Specification D.T.D. 59, and supplemented by coatings of varnishes, was also investigated in marinę conditions. The blocks were approximately4 in. long, 2 in. wide, and 0-5 in. thick, and were cut from cast plates of the alloy approximately 13 in. long and 10-5 in. wide. The composition of the plates (by analysis) is given in Table II.

The edges of the blocks were machined to a smooth finish, but the two main surfaces of the blocks were left in the “ as cast ” condition. The blocks were proyided with in. countersunk holes § in. from the ends of their longer axes, to enable them to be screwed down to a . stout teak frame. The screws used to secure the blocks to the frame were zinc-plated and were threaded in tu rn through a waxed paper washer, the alloy błock, and a “ Paxolin ” washer § in. square X f in. thick. The waxed paper was used to prevent possible damage to the

345

enamelled surface of the blocks while they were being screwed dow n; the Paxolin washers served to preyent lodgment of sea-water between the blocks and their supports.

Sutton and Le Brocq : The Protection of

T a b l e I I .— Composition of Cast Plates o f Magnesium Alloy, to Specifica- tion D.T.D. 59, TJsed for Corrosion Tests in Conjunction with Various Chemical Treatments and Enamelling Schemes.

Metallic Element.Composition (by Analysis), Per Cent.

Platę A. Platę B. Platę 0. Platę D. Platę E. Platę F. Platę G.

Aluminium . ZincManganese . Iron Silicon Magnesium .

6-653-480-190-070-22

89-39

6-483-220-190-070-19

89-85

6-663-230-210-070-18

89-65

6-503-250-170-050-20

89-83

6-953-370-220-070-13

89-26

6-803-220-190-060-20

89-53

6-643-400-200-070-18

89-51

Conditions of Exposure.The frame was secured to a gantry a t Felixstowe in such a manner

th a t the specimens were exposed, by the action of the tides, to sea- water and air for approximately equal intervals over a period of 8 months.

Observation of Loss of Metal by Corrosion.The amount of corrosion sustained by any one błock was determined

by weighing the błock after chemical treatm ent against corrosion but before the application of enamel, and again after exposure to sea-water and removal of the enamel film and products of corrosion. The difference between the two weights was taken as a measure of the resistance of the materiał to corrosion.

The enamel film and corrosion products were removed by allowing the specimens to stand in cold 5 per cent. caustic soda for 24 hrs., and then for 2 hrs. in a boiling 5 per cent. solution of potassium dichromate.

Before receiving protective chemical treatm ent, the specimens were cleaned by immersion for a few seconds in a solution containing 10 per cent. of nitric acid (sp. gr. 1-42) by volume. They were then washed with distilled water and immersed in the treatm ent bath. After treatm ent the specimens were washed with distilled water and dried.

The following chemical protective treatm ents were employed in these tests :

34 6


Bath 2.—This is the original 6-hr. chromate treatment.Bath 2A.—The bath was adjusted by means of caustic soda to the same

ps as th a t of chromate Bath 2 6-8) and was used under the sameconditions. This bath is equivałent to chromate Bath 2 less alumina.,

Bath 5.—Phosphate bath.Bath 4.—Chromate magnesium sulphate bath.Bath 2B.—Chromate ammonium snlphate bath.Bath 6.—Selenium treatm ent. This bath has been developed by Dr.

6 . D. Bengough and Mr. L. Whitby, of the Chemical Research Laboratory, Teddington,2, 3 who kindly carried out the treatm ent of the samples.

Of the above chemical treatments, treatm ent Baths 2B, 4, and 5 have been deve!oped as short-period baths in lieu of Bath 2, but have not previously been used as bases for the subsequent application of enamel. Bath 2A treatm ent had previously been found in one instance to give slightly better results than Bath 2 when used as a base for enamelling schemes. In conjunction with these chemical treatments the following enamelling schemes were employed :

(7) Undercoat: Barium Chromate in oil base. Finishing coat: V 85. (Specification D.T.D. 63).—The undercoat base was a long oil- varnish paint prepared from boiled linseed oil, albertol resin, and cobalt linoleate terebine drier. The pigment constituted approximately 50 per cent. of the total weight of the mixture. “ V. 85 ” is a varnish containing aluminium powder in a nitrocellulose base with gums.

(8) Undercoat: Barium Chromate in oil base. Finishing coat: V.W. 3 (Specification D.T.I). 63).— “ V.W . 3 ” is a varnish containing zinc oxide powder in a nitrocellulose base.

(9) Undercoat: Barium Chromate in oil base. Finishing coat: Barium Chromate in nitrocellulose base.—In this finishing coat, barium chromate was substituted for zinc oxide in the formuła for V.W. 3.

(10) Undercoat: Strontium Chromate in oil base. Finishing coat: V.W . 3.— In this undercoat strontium chromate was used in place of the barium chromate of Scheme (7).

(U) Undercoat: Zinc Chromate in oil base. Finishing coat: V.W .3 .—- In this undercoat zinc chromate replaced the barium chromate of Scheme (7).

(12) Undercoat: Titania (Titanium dioxide) in oil base. Finishing coat: Titania in nitrocellulose.—This scheme corresponds toScheme (7), using titania throughout instead of barium chromate.

347

Sutton and Le Brocą: The Protection of

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(13) Undercoał: Sulphur-treated oil pigmented with zinc chromate. Finishing coat: Cellulose varnish pigmented with aluminiumpowder.—This scheme was suggested by Dr. Bengough of the Chemical Research Laboratory, and was applied under his supervision.

In carrying out the exposure tests special attention was given to determining which enamelling scheme was the most efficient when used with a given chemical treatm ent. Bath 2 was included; its capabilities are now fairly well known. The tests were carried out in quadruplicate. Similar, bu t less complete tests, were also carried out with chemical treatm ents in Baths 2A, 2B, 4, and 5. These tests were carried out in duplicate, and the results are given in Table III.

T a b l e Y.—Results o f Corrosion Tests on Blocks of Magnesium Alloy to Specification D .T.D. 59 Protected by Chemical Treatments and Enamels including Treatments involving the Use of Selenium.

Chemical Treatment Applied to Blocks before Enamelling.

Enamelling Scheme Applied to Blocks after Chemical Treatment.

Loss in Weight in G-rm./ dm.B. of Surface of Blocks as a Result of Beach Kx-

■fiosuro Test for 8 Months.

Błock No. Loss in Weight.

Chromate, B ath 2 None G2 25Selenium, B ath 6 None G5 24Chromate, B ath 2

Selenium, B ath 6

(8) B aC r04 in oil -f V.W. 3 D 2 13-8G6 4-3

,, D3 4-2

Chromate, B ath 2 (13) Z nC r04 in sulphurized oil + alum inium cellulose finisli

G7 2-3E 8D4

0-330-18

Selenium, B ath 6 (13) Z nC r04 in sulphurized oil + alum inium cellulose finish

F i lB13

0-050-08

Tests were also carried out to determine which of the chemical treatm ents was the most efficient when used in conjunction with a giyen enamelling scheme. Scheme 8, which had up to this time been found to be the most efficient of those tested, was used for this purpose. The results of the present tests are given in Table IV, and those of experiments in which selenium treatm ent was used are given in Table V.

Discussion of Results of Tests on Cast Materiał to D .T.D. 59.Table III .—When chromate Bath 2 is used as a base for the sub-

sequent application of enamel, the best two enamelling schemes of those investigated would appear to be Scheme 11 (zinc chromate in oil

350

followed by zinc oxide in nitrocellulose) and Scheme 12 (titania in oil followed by titania in nitrocellulose). Both these enamelling schemes would appear to be considerably superior in protective value to Scheme 8 (barium chromate in oil followed by V.W. 3).

For the chromate pigments used in the present experiments in oil, undercoats under the same finishing coat (V.W. 3) the order of merit would appear to be : (1) zinc chromate, (2) strontium chromate, (3) barium chromate. Used as a pigment in a nitrocellulose finishing coat, barium chromate would appear to be possibly slightly better than zinc oxide. Thus, it would appear probable th a t zinc chromate would be considerably more efficient than zinc oxide if it were used under the same conditions.

Y. 85, aluminium powder in nitrocellulose base, appears, in generał, to be inferior as a finishing coat to Y.W. 3, zinc oxide in nitrocellulose base.

Table IV .—When used as a base for Enamelling Scheme 8 (barium chromate in oil followed by V.W. 3), treatm ent in Bath 2B would appear to be the best of those investigated. The superiority of this treatm ent over Bath 2 treatm ent when used as a base for the subsequent application of the enamels used is, on the basis of the present results, quite appreciable.

Table V .—There appears to be little difference between the resistance to corrosion of magnesium alloy to Specification D.T.D. 59 whether it be treated in chromate Bath 2 (Błock G2) or in the selenium Bath 6 (Błock G5). When supplemented, however, by Enamelling Scheme 8 (barium chromate in oil + V.W. 3) the selenium treatm ent would appear to be superior to the Bath 2 chromate treatment.

Enamelling Scheme 13 (zinc chromate in sulphurized oil -j- aluminium cellulose finish) appears to be superior to Scheme 8 (barium chromate in oil + Y.W. 3). Thus, with błock E8, the łoss due to corrosion was 0-33 grm./dm.2, whereas the mean łoss of blocks E6 and E10 (Table IV) was 1-6 grm./dm.2. The combination of the selenium treatm ent and Enamelling Scheme 13 (zinc chromate in sulphurized oil + aluminium cellulose finish) appears to be nearly as efficient as the combination of chromate Bath 2 treatm ent and Enamelling Scheme 11 (zinc chromate in oil + V.W. 3). Thus, with błock F i l , the loss due to corrosion was 0-05 grm./dm.2, whereas with blocks F9 and F10 (Table III, fifth group) the mean loss due to corrosion was 0-005 grm./dm.2.

The above experiments with the short-time chromate treatm ent bath 2B showed th a t it was somewhat corrosive in its action on the mild steel containers used. The contents of ammonium dichromate, potassium dichromate, and ammonia were accordingly increased slightly,

351


as shown in Table VI, and, as a result of this change the attack on the containers was much reduced.


T a b l e V I.— Compositions of Treatment Baths Containing AmmoniumSulphate.

Componcnt. Original Bath 2B. Modified Bath (Bath 3).

Ammonium sulphate . Ammonium dićhrom ate Potassium dićhrom ate . Ammonia, sp. gr. 0-880

3 grm./lOO c.c.0-650-750-33 c.c./lOO c.c.

3 grm./lOO c.c.1-51-50-5 c.c./lOO c.c.

Both the original and modified baths were suitable for use in aluminium containers. The modified bath (Bath 3) had the further advantage th a t the time of treatm ent could be reduced from 45 to 30 minutes. As in the case of the previous bath, the solution was maintained in a briskly boiling condition during treatm ent. No contamination of the bath by iron salts was experienced as the pu rangę over which the bath was worked (yH 5-8-6-7) was such as to ensure tb a t any ferric salts which might be produced as a result of the action of the bath on the C o n ta in e r , were converted into ferric hydroxide, and thus rendered insoluble.

P r o t e c t io n o f S h e e t M a t e r i a l s .

Two types of magnesium alloy sheet complying with Air Ministry Specifications D.T.D. 118 and 120, respectively, were used in the investigation. The sheets were of 14G, their compositions (by analysis) being given in Table VII.

T a b l e V II .— Composition of Sheets of Magnesium Alloy to Specifications D.T.D. 118 and 120.

Component. Alloy to Specification D.T.D. 118.

Alloy to Specification D.T.D. 120.

Aluminium, per cent. 6-86Zinc, per cent. . . . . 1-02Manganese, per cent. 1-96 0-19Iron, per cent. . . . . 0-04 0-04Silicon, per cent. . . . . 0-02 0-02Magnesium (by difference), per cent. 97-98 91-87

Magnesium alloys of the composition given in Table V II for the sheet to Specification D.T.D. 118 are suitable for lightly-stressed parts, or for parts which require welding. Alloys of a composition similar to tha t

352

of the sheet to Specification D.T.D. 120 are suitable for forgings and stampings, as well as for sheets.

For test purposes, the sheets were out into rectangular specimens 10 in. long by 3 in. wide. The majority of the tests were carried out in triplicate. In any one group of three, the specimens were drawn from widely separated portions of the original sheets so as to reduce the effects of possible irregularities in the original materiał.

Conditions of Exposure.For the beach exposure tests, the ends of the specimens were fitted

into shallow recesses formed in the wooden cross-bars of strong teak frames, and were held in position by means of wooden fillets. The fillets themselves were secured to the cross-bars by means of zinc-plated brass wood-screws which did not come into contact with the specimens and the frame, and fillets were painted with pigmented oil yarnish.

The beach exposure tests were carried out at Felixstowe over a period of 5 months. Protection of the test-pieces from stones and drifting m atter was afforded by galvanized-iron netting covers secured to the main frames.

Obserration of Loss of Metal by Corrosion.The amount of corrosion sustained by any one specimen was deter-

mined by weighing the specimen after chemical treatm ent against corrosion, bu t before the application of enamel, and again after beach exposure and removal of the enamel film and products of corrosion.

Observation of the Changes in the Mechanical Properties of Specimens as a Result of Chemical Treatment and Beach Exposure.

Comparative tests were carried out to determine the maximum stress and elongation values of the specimens as received, after chemical treatm ent, and in certain cases after beach exposure. One test-piece was cut from the centre of each specimen, the longest axis of the test- pieces being co-linear with th a t of the specimen. The test-pieces were 8 in. long and 0-5 in. wide X 2 in. between parallels.

As shown recently by A. Portevin,6 machining of test-pieces from sheets which have undergone corrosion test is more satisfactory than testing of samples which have been submitted to corrosion test in the form of machined test-pieces, sińce in the latter case attack on the edges occurs in exaggerated form. In the case of thin sheets, serrations on the edge render the test-piece liable to fail prematurely.

353

Magnesiuni Alloys Against Corrosion

Sutton and Le Brocą: The Protection ofPreparation of Specimens for Corrosion Tests.

The protective film present on. the specimens in the “ as received ” condition as a result of chromate treatm ent by the manufacturer, was removed by rubbing the specimens lightly with a rag moistened with a mixture of pumice powder and water. After this treatm ent the specimens were momentarily dipped in a 10 per cent. solution (by volume) of nitric acid in water, and were then rinsed in distilled water and afterwards immersed in one or other of the following baths :

(A) Chromate Bath 2.(B) Chromate Bath 3.(C) Selenium Bath 6A. This bath is a modification of Bath 6 and

consists of an aąueous solution of 2 per cent. sodium selenite plus0-25 per cent. sodium chloride, containing ortho-phosphoric acid (sp. gr. 1-75) to the extent of 15 c.c. per litre of solution, as recommended by Bengough and Whitby.

The time of treatm ent varied from 2 to 4 minutes. After immersion, the specimens were removed and allowed to drain until dry, when they were washed and dried between blotting paper. Some of the specimens were finally heated to 100° C. in a steam oven for 30 minutes. The treatm ents were carried out a t Teddington under the supervision of Dr. Bengough.

In conjunction with these chemical treatm ents, the following enamelling schemes were employed :

(D) Blach Stoving Enamel.—This was of the “ stand oil ” type and was in accordance with Specification D.T.D. 56A. I t was applied in two thin coats, each coat being air dried for 2 hrs. and then stoved for 2 hrs. a t 160° C.

(E) Clear Stoving Varnish.—The varnish was prepared from synthetic resins. I t was applied in two thin coats, each coat being air dried for 2 hrs. and then stoved for 4 hrs. a t 120° C. The varnish complied with Specification D.T.D. 56A.

(E) Low Bake Black Enamel.—This was prepared from synthetic resins and was applied in the same fashion as in Scheme (E). I t complied with Specification D.T.D. 56A.

(G) “ Barium Chromate ” Stoving Enamel.—This was of the long oil- yarnish type and was pigmented with barium chromate. I t was applied in the same fashion as in Scheme (E).

(H) “ Strontium Chromate ” Stoving Enamel.—This scheme was similar to Scheme (G) except th a t strontium chromate was used as pigment instead of barium chromate.

35 4

(J) Undercoat: Barium chromate in oil base. Finishing coat: Y.W . 3. (Specification D.T.D. 63.)—This scheme corresponds to Scheme 8 of the series of lists on castings. The undercoat base was a long oil-varnish paint prepared from boiled linseed oil, albertol resin, and cobalt linoleate terebene drier. The pigment constituted approximately 50 per cent. of the total weight of the mixture. The undercoat complied with Specification D.T.D. 62. V.W. 3 is a varnish containing zinc oxide powder in a nitrocellulose base. Both the undercoat and the finishing coat were air dried only.

(K) Undercoat: Strontium chromate in oil base. Finishing coat:Y.W . 3. (Specification D.T.D. 63.)—This Scheme was similar inall respects to Scheme (J) except th a t strontium chromate was used as a pigment in the undercoat instead of barium chromate, and corresponds to Scheme 10 used in the tests on castings.

(L) Undercoat: Sulphur-treated oil pigmented with zinc chromate.Finishing coat: Aluminium powder in nitrocellulose.—This scheme corresponds to Scheme 13 of the series of tests on castings.

With the exception of Scheme (L) the above enamelling schemes were applied by the same operator to produce, as nearly as possible, a finał increase in weight due to enamel of 2 oz. per square yard of metal surface. Both the undercoats and the top coats were applied by spraying.

The schemes were selected chiefiy with the object of determining whether stoving enamels were superior to. air-drying enamels for the prevention of corrosion of magnesium alloys. The proprietary stove enamelling schemes described above (Schemes (D), (E), and (F)) have been found to give good results on metals other than magnesium alloys. The air-drying enamels of Schemes (J) and (K) were the same as those used on the cast magnesium alloy samples to Specification D.T.D. 59. In those tests it was found th a t Scheme (K), in which the pigment used was strontium chromate, was superior to Scheme (J), in which barium chromate was used, but th a t a scheme in which zinc chromate was used as a pigment was better than either of Schemes (J) or (K). At the time of the commencement of the work on sheet materiał, this latter result was not apparent, and hence this scheme was not included in the present work.

Results of Corrosion Tests (Weight Determinations).The loss of metal from the various specimens as a result of corrosion

by sea-water is given in Tables V III and IX.I t would appear from Table V III tha t, taken over a period of 5

months, only slight losses of metal occurred from magnesium alloy355


sheet specimens to Specification D.T.D. 118 when treated in either chromate Bath 2 or chromate Bath 3 before enamelling, except in the case where strontium chromate stoving enamel was used. Used in conjunction with this alloy chromate Bath 2 appeared to be possibly slightly superior to chromate Bath 3.

Magnesium alloy to Specification D.T.D. 118, when treated in either modification of the selenium bath examined, appeared to suffer slightly greater metal loss when not subsequently enamelled, than when treated in chromate B ath 2 and exposed in the same conditions. W ith this alloy, stoving enamels with one exception (strontium chromate stoving enamel) appeared to be somewhat superior to air-drying enamels.

The poor protection obtained with scheme (H) may possibly be due to the destruction either of the enamel base or of the film produced on the metal by the chromate bath. Strontium chromate is probably more reactive than barium chromate. I t hiń been observed th a t, in generał, less rubbing with abrasives is requi co remove the film produced on magnesium alloys to Specification D .i.D . 118 than on other magnesium alloys.

From Table IX it is elear th a t magnesium alloy to D.T.D. 120 is much less resistant to corrosion than magnesium alloy to D.T.D. 118 when protected in the same manner. When applied to alloy to D.T.D. 120 and used in conjunction with an enamel, chromate Bath 3 would appear to be, in generał, considerably superior to chromate Bath 2 for protective treatm ent of magnesium alloys. W ith this alloy, air-drying enamelling scheme (K) (strontium chromate in oil followed by V.W. 3) was considerably superior to the other enamelling schemes investigated.

Results of Corrosion Tests (Change in Mechanical Properties).

Owing to the badly corroded condition of many of the specimens of magnesium alloy sheet to Specification D.T.D. 120 which had been stove enamelled, tests to determine mechanical properties of the sheet after exposure to sea-water were confined to stove enamelling schemes(E) and (F) and to air-drying schemes (J), (K), and (L). For com- paratiye purposes, mechanical tests on unexposed materiał were also carried out. The results of these tests are shown in Tables X, X I, and X II.

From Table X it would appear th a t replacement of the original chromate treatm ent film produced by the rapid chromate treatm ent a t the manufacturer’s works on either alloy D.T.D. 118 or D.T.D. 120 by a fresh chemically produced film has had little effect on the mechanical properties of these alloys (so far as these properties were examined).

356



These properties also do not appear to have been altered by storage of the chemically treated alloys for 5 months under laboratory conditions.

T a b l e V III.— Loss in Weight in Grm.ldm.2, of Specimens of Magnesium Alloy to Specification D.T.D. 118 as a Result of Beach Exposure for 5 Months.

Chromate Bath 2. Chromate Bath 3.

Enamelling Scheme.Sheet No.

Loss in Weight,

G-rm.

MeanLoss,G-rm.

Sheet NoLoss in Weight,

Grm.

MeanLoss,Grm.

(D) Black stoying enamel CAlCCICG1

0-0130-0110-014

0-013CB1CDICF1

0-1080-0700-145

0-108

(E) Clear stoving enamel CA:; Cf ' CG.

•n

0-0160-0370-013

0-022CB2CD2CF2

0-0120-1230-027

0-054

(F) Low bake black enamel CA3CC3CG3

0-1680-0480-005

0-074CB3CD3CF3

0-0110-0680-058

0-046

(G) Barium chromate stoving enamel

CA4CC4CG4

0-0760-0300-282

0-129CB4CD4CF4

0-0610-1070-099

0-089

(H) Strontium chromate stoving enamel

CA 5 CE5 CG5

3-94 5-264-32

4-51CB5CD5CH5

8-084-563-54

5-39

(J) Barium chromate in oil air-drying enamel + V.W. 3

CA6CC6CE6

0-0550-0560-081

0-064CB6CF6CH6

0-1120-113 0-112

(K) Strontium chromate in oil air-drying enamel + V.W. 3

CC5CE1CG6

0-0180-0300-111

0-053CD6CF5CHI

0-1000-0520-286

0-146

Chromate Bath 2. Selenium Treatment Bath 6A.

No enamel applied after chemical treatm ent

CE2CE3CE4

2-422-121-68

2-07CA7*CB7*

2-192-14 2-16

CC71 CD7t

2-502-68 2-59

* Four m inutes’ treatm ent in selenium bath.t Four m inutes’ treatm ent in selenium bath, then heated to 100° C. for 30

minutes.

From Table X I it of alloy D.T.D. 118,

z

would appear th a t when used for the protection chromate Bath 2 and chromate Bath 3 were


approximately equal in their protective eflect when supplemented by enamel. Of the enamels investigated, the stoving enamels appeared to be slightly superior to the air-drying enamels. From Table X II it would appear th a t when used as a basis for the applioation of an enamel, ohromate Bath 3 was considerably superior to chromate Bath 2 for the protection of alloy D.T.D. 120. W ith this alloy enamelling scheme (K) (strontium chromate in oil air-drying enamel -f- V.W. 3) appeared to be slightly better than the stoving enamels investigated.

T a b l e IX .—Loss in Weight in Grm./dm? o f Specimens of Magnesium Alloy to Specification D .T.D. 120 as a Result of Beach Exposure for5 Months.


Enamelling Scheme.SheetNo.

Loss in Weight,

Grin.

MeanLoss,Grin.

SheetNo.

Loss in Weight,

Grrrl.

MeanLoss,Grm.

(D) Black stoving enamel FC5FE1FG5

9-278-937-35

8-52FB IFD1FH1

4-23

3-373-80

(E) Clear stoying enamel FC4FE4FG4

13-00 (13-00)FB2FD2FH 2

2-662-442-26

2-45

(F) Low bake blaek enamel FA5FC3F E 6

7-253-167-85

6-09FB3FD3FH3

0-841-43 1-57

1-28

(G) Barium chrom ate stoying enamel

FA3FC1FG3

4-83 2-725-45

4-34FB4FD4FH 4

3-624-90 4-93

4-48

(H) Strontium chromate stoying enamel

FA4FC2FG2

3-331-452-80

2-53FB5FF4FH5

0-841-192-73

1-59

(J) Barium chrom ate in oil air-drying enamel + V.W. 3

FA 6FE5FG1

5-516-77 3-96

5-41F B 6F D 6FF3

2-783-63 2-80

3-07

(K) Strontium chromate in air-drying enamel + V.W. 3

FC6FE2FG 6

0-3680-2910-226

0-295FD5FF2F H 6

0-1290-3240-300

0-251

N o te —W here no figurę is giyen for loss in weight after exposure to sea-water th e specimen had disintegrated.

When used without the subsequent application of enamel, Bath 6A selenium treatm ent (Table XI) appeared to give rather better results on alloy D.T.D. 118 than chromate Bath 2. A modification of this

358

treatm ent, in which the specimens were heated to 100° C. after immersion in the selenizing bath, did not give as good results as chromate Bath 2.

Specimens selenized and then enamelled in accordance with scheme (L) (zinc chromate in sulphur-treated oil + aluminium powder in nitrocellulose) gave results slightly inferior to those obtained with the chromate treatm ents followed by enamelling schemes (E), (F), and (J).


T a b l e X.—Mechanical Properties of Magnesium Alloy Sheets to Speci- jications D.T.D. 118 and 120 after Yarious Chemical Treatments. Specimens Not Exposed to Corrosive Conditions.

Alloy D.T.D. 118. Alloy D.T.D. 120.

SheetNo.

Maxi- mum Stress, Tons / in.2.

Mean.

Elong- ation

on 2 in., Per

Cent.

Mean. SheetNo.


Mean.

Elong-ation

on2 in., Per

Cent.

Mean.

Sheet as receiyed CB9CF9

13-414-0 13-7 6-0

7*0 6-5 FA7FE7

18-518-7 18-6 11-0

10-0 10-5

Chromate Bath 2 tested immediately

CC8CF8

13-112-7 12*9 7-0

5*5 6-3 FC7FF7

18-318-9 18-6 9-5

12-0 10*8

Chromate Bath 2 tested after 5 months

FE3 19-3 19-3 11-0 11-0

Chromate Bath 3 tested immediately

CB8CD8

13-312-6 12-9 6-0

6-0 6-0 FB7FD7

18-718-6 18-7 10-5

13-0 11-8

Chromate B ath 3 tested after 5 months

CH4CE8

12-212-5 12*4 8-0

6-0 7-0

Discussion of Results on Enamelled Sheet Materials.There would appear to be a considerable advantage, in generał, in

the use of Bath 3 rather than Bath 2 for the protection of magnesium alloys which are to be subseąuently enamelled. W ith Bath 3 the treatm ent time is very much shorter than with Bath 2, and the results obtained would appear to be equal to or better than those obtained with Bath 2. Insufficient experiments have been carried out so far to permit any generał conclusions to be reached as regards the relative merits of the chromate batbs and the selenium treatm ent when used in conjunction with enamels. I t was observed, however, th a t red pustules were formed on the enamelled surface of the specimens which had received selenium treatm ent, after they had been exposed to sea-water, although the amount of corrosion of the underlying alloy was slight. This efiect may be disadyantageous for certain purposes.

The stoving enamels examined do not appear to be superior in generał to the better of the two air-drying enamelling schemes tested. An im portant advantage of an air-drying enamelling scheme is th a t it

359


T a b l e X I .— Mechanical Properties of Specimens of Magnesium Alloy to Specification D.T.D. 118 ąfter Beach Exposure for 5 Months.




Mean.

Elongation

on2in.,Per

Cent.

Mean. SheetNo.


Mean.

Elongation

on2in.,Per

Cent.

Mean.

(E) Clearstoving enamel CA2CC2CG2

12-813-012-8

12-97-56-05-0

6-2CB2CD2CF2

13-012-912-9

12-96-06-05-0

5-7

(F) Low bake black enamel

CA3CC3CG3

13-013-413-0

13-17-05-06*5

6-2CB3CD3CF3

13-113-012-5

12-95-55-04-0

4-8

(J) Barium chromate in oil air-drying enamel + Y.W. 3

CA6CC6CE6

13-112-712-8

12-95-04-54-0

4-5CB6CF6CH6

12-713-2 12-9

6-04-5 5-3

(K) Strontium chromate in oil air-drying enamel -j- C.W. 3

CC5CElCG6

12*512-012-9

12-53-5 6-04-0

4-5CD6CF5CHI

11;712-012-6

12-13-54-5 8-0

5-3

Chromate Bath 2. Selenium Treatment, Bath 6A.

No enamel CE2CE3CE4

8-39-5

10-79-5

3-02-52-5

2-7CA7*CB7*

11-611-3 11-5 5-5

4-0 4-8

CC7 f CD7f

10-15-9 8-0 3-5

1-0 2-3

(L) Zinc chromate in sulphur-treated oil -j- Al powder in nitrocellulose

CE7JCF7J

13-212-6 12-9 6-0

4*0 5-0

* Four minutes’ treatm ent in selenium bath.f Four minutes’ treatm ent in selenium bath, then heated to 100° C. for 30 minutes. j Two minutes’ treatm ent in selenium bath.

T a b l e X II .— Mechanical Properties of Specimens of Magnesium Alloy to Specification D.T.D. 120 as a Result of Beach Exposure for 5 Months.



Maxi-mumStress,Tons/in.2.

Mean.

Elongation

on2in.,Per

Cent.

Mean. SheetNo.

Maxi-mumStress,Stress,in.a.

Mean.

Elongation

on 2 in., Per

Cent.

Mean.

(E) Clear stoying enamel FC4FE4EG4

FB2FD2FH2

18-318-018-4

18*211-510-013-0

11-5

(F) Low bake black enamel

FA5FC3FE6

18-5 6-2 12-0 4-0FB3FD3FH3

18-511-718-3

16-213-0

1-513-0

9-2

(J) Barium chromate in oil air-drying enamel + Y.W. 3

FA6FE5FG1

16-62-65-3

8-25-01-01-5

2-5FB6FD6FF3

13-718-05-3

12-32-08-51-0

3-8

(K) Strontium chromate in oil air-drying enamel + Y.W. 3

FC6FE2FG6

18-517-517*3

17-810-08-07-0

8-3FD5FF2FH6

18-517-916-3

17-612-0

9-56-0

9-2

Note.-—Where no figurę is given for maximum stress or elongation the specimen was too fragile to permit a test-piece to be machined.

360

may be applied in the field, and th a t the apparatus required for its application is of the simplest character.

Tables X III and XIV show th a t loss in weight and loss in tensile strength indicate the degree of corrosion with fair agreement, bu t th a t the loss of elongation was less informative.


T a b l e X III .— Correlation of Observations on Loss in Weight and Loss of Tensile Properties. Magnesium Alloy D.T.D. 120.


Enamelling Scheme. Mean Loss in Weight,

Grm./dm.2.

Loss of Tensile

Strength, Per Cent.

Loss of Elongation

Value, Per Cent.

Mean Loss in Weight,

Grm./dm.2.

Loss of Tensile

Strength, Per Cent.

Loss of Elongation

Yalue, Per Cent.

(E) Clear stoving enamel . 2-45 2*2 nil

(F) Low bake black enamel . 6-09 66*6 61-9 1*28 12*9 12*4

(J) Barium chromate in oil air-drying enamel + V.W.3 5*41 55*9 76*1 3*07 33*8 63*8

(K) S trontium chrom ate in oil air- drying enamel + V.W. 3 0*295 4*3 21*0 0*251 5*4 12*4

T a b l e XIV.— Correlation of Observations on Loss in Weight and Loss of Tensile Properties. Magnesium Alloy D.T.D. 118.


Enamelling Scheme. Mean Loss in

'Weight, Grm./dm.2.

Loss of Tensile

Strength, Per Cent.

Loss of Elongation

Value, Per Cent.

Mean Loss in Weight,

Grm./dm.a.

Loss of Tensile

Strength, Per Cent.

Loss of Elongation

Value, Per Cent.

(E) Clear stoving enamel . 0-022 5-8 4-6 0-054 5-8 12

(F) Low bake black enamel . 0-074 4-4 4-6 0-046 5-8 26-1

(J) Barium chromate in oil air-drying enamel + V.W.3 0-064 5-8 30-8 0-112 5-8 18-5

(K) S trontium chrom ate in oil air- drying enamel + V.W. 3 0-053 8-8 30-8 0-146 11-7 18-5

P r ę t a k a t io n o f S p e c i m e n s f o r C h r o m a t e T r e a t m e n t .

I t is undesirable th a t parts machined to fine tolerances should be cleaned in nitric acid baths in preparing them for chromate treatment,

361


owing to the loss of metal which may occur if the immersion is more than momentary. Immersion for 30 minutes or more in a ho t 2 per cent. solution of Caustic soda was found to be effective in removing grease and foreign m atter resulting from machining operations and repeated handling. Experiments were made on magnesium alloy sheet D.T.D. 120 of the following composition :

Per Cent.

Aluminium . . . 7-18Zinc . Manganese . Silicon Iron . Magnesium

1-170-280-010-05

remainder

the specimens employed measuring 10 cm. X 3-5 cm. X 0-2 cm. Com- parative tests were made to ascertain the effects of simple immersion and electrolytic treatm ents as cathode in caustic soda solution and in

T a b l e XV.—Loss in Weight in Grm./dm? of Specimens of Magnesium Alloy to Specifcation D.T.D. 120 as a Result of Exposure to Inter- mittent Sea-Water Spray Test for 3 Months. Specimens Cleaned by Yarious Methods and then Chromate Treated, Bath 2.

Speci-menNo.

Cleaning Bath. Time,Minutes.

Temperatura,

°0 .

CurrentDensity,

Amp./ft.2.

Loss by Corrosion,

Grm.

MeanLoss,Grm.

HA2 Alkaline cleaner 30 95 0-20HD1 9 9 9 9 30 95 0-19 0-22HF2 9 9 9 9 30 95 0-28

HA1 Alkaline cleaner, cathodic 2 95 20 0-73HC3 » » » 2 95 20 0-62 0-59HF1 9 9 9 9 9 9 2 95 20 0-41

HA3 Alkaline cleaner, cathodic 30 95 20 0-48HC1 9 9 9 9 30 95 20 0-47 0-50HF3 9 9 30 95 20 0-56

HB3 Caustic soda 30 95 0-34i!

HC2 9 9 9 9 30 95 0-63 0-60 :HE2 9 9 9 9 30 95 0-83

HB1 Caustic soda, cathodic 2 95 20 0-48 ŚHD3 9 9 9 9 9 9 2 95 20 0-46 0-46HE3 9 9 9 9 9 9 2 95 20 0-44

HB2 Caustic soda, cathodic 30 95 20 0-45HD2 9 9 9 9 9 9 30 95 20 0-58 0-45H E 1 9 9 9 9 9 9 30 95 ' 20 0-33

362

an alkaline cleaning bath consisting of a 5 per cent. solution of a mixture contammg : Parts by Weight_

Hydrated sodium carbonate Na2C03-10H20 . 74-5Anliydrous sodium metasilicate Na2Si03 . . 24-5

1 *0Sodium oleate . • • ■ • •The original chromate film present on the sheets as received was

removed by rubbing the specimens with pumice powder and water. The specimens were then subjected to the various cleaning treatments, then chromate treated in Bath 2. They were then subjected to the interm ittent sea-water spray test for 3 months, after which they were cleaned free from corrosion product and the loss of metal by corrosion determined by change in weight. Table XV contains the results of the


T a b l e X V I— Composition and Conditions of Use of Chemical Treatment Baths.

(Composition given in Grm./lOO c.c. unless otherwise stated.)

Bath2.

Bath2A.

Bath2B.

Bath3.

Bathi .

Bath5.

Bath6.

Bath 1 6A.

AluminaAmmonia (d 0*880). Ammonium dichro-

m ate .Ammonium sulphate Chromie an h y d rid e . Manganese sulphate

anhyd.Magnesium sulphate

0 -3 3 t

0-653-0

Ó -5t

1-53-0

I

10-0

0-5

1-0

Orthophosphoric aeid .

Orthophosphoric acid solution (d 1-75) .

Potassium dichrom ate .

Potash alum . Selenious acid Sodium selenite Sodium chloride Sodium hydroxide . Sodium sulphate aq

1-51-0

0-5

1-5

0-21-5

0-75 1-5

i-o

1-0

10-0

0-5

1-5f

2-0 0-25

Time of treatm ent . 6hrs.

6hrs.

45min.

30min.

2min.

30min.

10min.

2-4min.

Tem perature of treatm ent, °C . . 9 5 -

10095-100

100*

100*

100*

100*

20 20

* Boiling.363

t C.c.

tests, which show th a t the specimens which had been cleaned in the alkaline cleaning bath without electric current suffered the least corrosion. With th a t bath the use of electric current was dis- advantageous, and with the caustic soda bath it was slightly advantageous.

SUMMARY OF CONCLUSIONS.

A short-tmie chromate treatm ent bath has been evolved which is suitable and conyenient for the treatm ent of cast and wrought forms ofthe two types of magnesium-rich alloy most commonly used a t the present time.

In the absence of supplementary coats of organie protectives, the film produced m the short-time chromate treatm ent bath affords slightly less protection than th a t produced in the 6-hr. treatm ent (Bath 2), but when supplemented by enamels the short-time treatm ent gives somewhat better protection than the 6-hr. treatm ent and about the same degree of protection as selenium treatm ent when each form of treatm ent is supplemented by the most appropriate enamelling scheme.

The best supplementary protectives for chromate-treated materiał of those examined were zinc and strontium chromate oil-base air-drying undercoats foliowed by zinc oxide-pigmented nitrocellulose vamish

For preparing pieces for chromate treatm ent, simple immersion ina hot alkaline carbonate-silicate-oleate cleaning bath was found togive better results as regards the protective efiect of the subseouentchromate treatm ent than electrolytic treatm ent in the same bath ortreatm ent m caustic soda solutions with or without the use of electric current.

R e f e r e n c e s .

2 p ' ^ UtB0n a,ld h P - Le Br°cq, •/. Inst. Metals, 1931, 46, 53-72 a r n ' ®enS°ug}' alK* L. W hitby, J . Inst. Metals, 1932, 48, 147-1584 Sutton a n l ° T ? T ? T T Ł J ' ItU ł‘ MetaU’ 1933’ 5 2 ‘ 85- 88‘Sutton and Le Brocq, J Inst. Metals, 1931, 46, see footuote, p. 54.

Sutton and Le Brocq, J . Inst. Metals, 1931, 46, 65 66A. Portevin, Rev. Met., 1934, 31, 212-213

Protection of Magnesium Alloys Against Corrosion

3 6 4

PAPER No. 710. This paper is copyright. I t may be reprinted, wholly or in part, in the Press (w ith due acknowledgment) a fter being presented a t the A utum n M eeting ot the In s titu te to be held on September 9-12, 1935, in Newcastle-upon-Tyne. The Institu te as a body is no t responsible for the statem ents or opinions expressed m this paper, on which written disscusion m ay be sent to the Secretary no t la ter than October 1, 1935.

ELECTRON DIFFRACTION EXAMINATION OF PROTECTIYE FILMS DEPOSITED ON MAGNESIUM AND MAGNESIUM ALLOYS BY THE R.A.E. DICHROMATE PROCESS.*

By H. G. H O P K IN S ,t A.R.C.S., B.So.

S y n o p s is .

The proteetive films, in generał, yielded diffuse diffraction rings. I t is concluded th a t the films consist of very smali crystals orientated a t random. I t is ten ta tively suggested th a t the diffracting lattice is pseudo- m orphic magnesium oxide.

S p e c i m e n s of alloys A.M. 5 0 3 , D.T.D. 88A, and commercial magnesium coated with. protectiye films by two different treatments were supplied by the Royal Aircraft Establishment, Farnborough. The composition of the alloys and the magnesium is given in Table I.

T a b l e I .

A.M. 503. D.T.D. 88A. CommercialMagnesium.

Aluminium, per cent. 0-07 7-73 0-22Zinc, per cent. . . . . 1*15Iron, per cent. . . . . 0-03 0-03 0-02Manganese, per cent. 1-79 0-19 TracęSilicon, per cent. . . . . 0-03 0-04 0-10Copper, per cent. . . . .Magnesium, per cent. remainder remainder remainder

The specimens had been prepared ag described below.Treatment (a).—Samples, polished as for microscopic examination,

were immersed momentarily in a 10 per cent. solution of nitric acid in water, rinsed in distilled water, and then immersed for 6 hrs. in a boiling acjueous solution of the composition : potassium dichromate

* Manuscript reeeived May 10, 1935. t Physies Departm ent, Royal College of Science, London.

Note to Abstractors and Other Readers.—This paper will be published, in perm anent form, in the Journal of the Institute of Metals, Vol. LVII, 1935. Reference should accordingly be as follows: J . Inst. Metals, 1935, 57 (Advance copy).

365

710

1-5, alum 1-0, sodium hydroxide 0-5 per cent. After treatm ent the samples were rinsed in distilled water and dried.

Treatment (b).—Samples were prepared and cleaned as above, and then immersed for 45 minutes in a boiling aąueous solution of the composition : potassium dićhromate 1-5, ammonium dićhromate 1-5, ammonium sulphate 3, ammonium hydroxide (sp. gr. 0-880) 0-5 grm./ 100 c.c. Samples were rinsed in distilled water and dried.

The protective films were examined by electron difiraction, using apparatus similar to th a t originally designed by Professor G. P. Thomson.1

The following results were obtained.

A.M. 503.Treatment (a).—Five samples taken from the protected alloy were

examined. The photographs of the difiraction pattern all gave a high generał background intensity, bu t in all cases rings were detectable. The rings obtained from the first two specimens were fairly sharp; measurement of the rings gave the following mean planar spacings :2-59, 2-25, 1-98, 1-68, 1-48, 1-21, 1-02 A. No great accuracy is claimed for these values owing to the large amount of background and the smali number of plates exposed. The other three specimens examined yielded four diffuse rings, the innermost being more diffuse than the others. These rings corresponded to spacings of 2-16, 1-47, 1-15, 0-85 A.

Treatment (b).—Several plates were exposed, using a number of difierent specimens of this film. No pattern could be obtained owing to the specimen charging up.

D.T.D. 88A.

Treatment (a).—No sharp rings could be obtained from this film. Several specimens were tried, bu t only diffuse difiraction rings were given. The pattern was identical with th a t obtained from the last three specimens of the A.M. 503 (a) film. Background intensity was again high.

Treatment (b).—The pattern obtained again consisted of diffuse rings similar to those obtained from the (a) film. Some difficulty was experienced due to the specimens charging up, but this phenomenon was not so marked as in the case of the film formed on A.M. 503 by Treatment (b). The plates all showed a high background intensity.

CoMMERCIAL MAGNESIUM.

Treatment (a).—Diffuse rings only were obtained; measurement of these rings was difficult, owing to the high background intensity,

366

Hopkins : Examination of Protective Films

Deposited on Magnesium and Magnesium Alloys

but the results indicated th a t the diffuse pattern was the same as tha t already described.

Treatment (b).—Charging up of the specimens was so serious tha t no pattern could be obtained.

D is c u s s io n o f R e s u l t s .

From a comparison of the measurements made on the sharp and diffuse rings obtained from the various films formed by Treatment (a), and their relative intensities, it seems reasonable to suggest th a t the diflracting lattice is the same for all the specimens from which patterns were obtained.

The fact tha t, in generał, diSuse ring patterns were obtained suggests th a t the crystals are smali and unorientated. I t seems, however, th a t local variations in crystal size occur a t least in the case of the Treatment (a) deposit on A.M. 503—as otherwise no variation in the sharpness of the pattern would have been observed.

From the values of the spacings obtained it is impossible to deduce the structure with any certainty, but it is suggested tentatively th a t th e results, with the exception of the 1-98 A. spacing are consistent with a simple hexagonal structure with the approximate constants . a = 2-99 A., axial ratio = 1-55. I t is perhaps worth mentioning th a t this is the structure suggested by Finch and Quarrell for a new form of magnesium oxide.2

The films formed by Treatment (6) were not so smooth as those formed by Treatment (a), due to varying thickness, and it is, therefore, probable th a t the charging up was due to the electron beam impinging on the thick spots.

The results show th a t the film produced by Treatment (b) on D.T.D. 88A. has the same structure as th a t already described for the Treatment (a) deposit.

G e n e r a l C o n c l u s io n s .

(1) The surface films examined consist of smali crystals orientated a t random with respect to the surface. The protective ąuality of the film is probably attributable to the smali crystal size.

(2) I t is possible th a t hexagonal magnesium oxide is present on the protective surfaces submitted, bu t the evidence is not conclusive.

(3) The films formed by Treatment (6) are locally much thicker than the Treatment (a) films.

367

A c k n o w l e d g m e n t s .

In conclusion, I wish to express my gratitude to Professor G-. P. Thomson for the interest th a t he has taken in the work.

R e f e r e n c e s .

1 G. P. Thomson, Proc. Roy. Soc., 1930, [A], 128, 641.2 G. I. F inch and A. G. Quarrell, Proc. Roy. Soc., 1933, [A], 141, 398.

Examination of Protective Films

368

PAPER No 711. This paper is copyright. I t may be reprinted, wholly or in Part, in the Press (w ith due acknowledgment) a tte r being presented a t th e A utum n Meeting of the In s titu te to be held on Septem ber 9-12, 1935, in Newcastie-upon-Tyne. The In s titu te / | as a body is no t responsible for the statem ents or opmionswhieh written discussion m ay be sent to the Secretary no t la ter than October 1, lSMo.

ALLOYS OF MAGNESIUM. PART III.—CON- STITUTION OF THE MAGNESIUM-RICH ALLOYS CONTAINING ALUMINIUM AND CADMIUM.*

By J . L. HAUGH TO N,f D .Sc., Membeb o i- C o u n c i l , and R . J . M. PA Y N E ,t B.Sc., Membek.

Sy n o psis .The addition of cadmium to magnesium-aluminium alloys depresses

the liouidus slightly, 20 per cent. cadmium lowering the hąuidus temperature of an 80 per cent. magnesium-20 per cent. aluminium alloy by about 50° C., bu t has practically no effect a t th e tem peratura of the alum inium -m agnesium eutectic. I t also reduces the solubuity ol aluminium in magnesium to a smali extent. No new phases are iound up to 20 per cent. of each added element, bu t a ttention is directed to an abnormal form of precipitation which was found in some of the alloys.

T h is paper forms P art I I I of the investigation of the constitution and mechanical properties of the alloys of magnesium which is being conducted at the National Physical Laboratory under the superyision of Dr. C. H. Desch, F.R.S., and at the instigation of the Alloys Sub- Committee of the Aeronautical Research Comrnittce.1, 2

This particular research was instituted to provide a theoretical basis for the work on the mechanical properties of magnesium contaimng additions of cadmium (the presence of which improves the ductility of the alloys) and of some other metal (in this case aluminium) to pro- yide strength and hardness. The work on the mechanical properties has been directed to strike a balance between the opposing effects of cadmium and aluminium and to obtain an alloy which possesses in fair measure both ductility and strength, as described in P art II of these investigations. The research was also intended to furnish data for investigation of the possibility of improving the alloys by precipitation-hardening. The rangę of alloys examined was restricted to those containing not more than 20 per cent. of any one added element.

* M anuscript received April 18, 1935.t Principal Scientific Officer, Departm ent of Metallurgy and Metallurgical

Chemistry, National Physical Laboratory, Teddington.1 Assistant I I I , D epartm ent of Metallurgy and Metallurgical Chemistry,

National Physical Laboratory, Teddington.

Note to Abstractors and Other Eeaders.—This paper will be published, in perm anent form, in the Journal of the Institute of Metals, Vol. LVII, 1935. Reference should accordingły be as follows: J . Inst. Metals, 1935, 57 (Advance copy).

369

Haughton and Payne :

P r e v io u s W o r k .

(a) The Binary Systems.I. The Magnesium-Cadmium Senes.— The constitution of these

alloys has been studied by Hume-Rothery and Rowell,3 and the diagram they obtained is given so far as the present work is concerned (i e up to 20 per cent. Cd), in Fig. 1. I t will be seen th a t the alloys consist ot a homogeneous solid solution.

II. The Magnesium-Aluminium Senes.—Fig. 6 is based on the diagram of Hanson and Gayler.4 Certain modifications in the solid solubility lme have been suggested by other workers. The diagram has been modified to agree with results obtained by the present authors, which are referred to later in this paper.

III. The Cadmium-Aluminium Series.—This system has beenstudied by Gwyer, 5 and by Hansen and Blumenthal.6 The phases occurrmg m these alloys, however, do not play any part in the ternary system. J

(b) The Ternary System.Valentin and Chaudron 7 h a v e s tu d i e d t h e ternary a l lo y s o f m a g -

nesium, aluminium, a n d c a d m iu m , a n d h a v e m a p p e d i s o th e r m a ls o f t h e l i ą u i d u s s u r f a c e f o r a la r g e p a r t o f t h e d ia g r a m . Little m o reI n f o r m a t io n t h a n t h i s , h o w e v e r , w a s g iv e n .

M a t e r i a l s a n d M e t h o d s .

The magnesium used was supplied by the British Maxium Company, and contamed about 99-94 per cent. magnesium. A typical analysis is as follows:

Per Cent.C°PPe r ........................................................................ 0-006Iron .................................................................................0-038Aluminium . . . . . . 0-010

Chemically pure cadmium and aluminium containing silicon 0-08 and iron 0-09 per cent. were used.

The alloys were usually madę up in 300-grm. melts in stainless- steel crucibles under flux, and it was soon found th a t great care was necessary in melting the metals together if loss of the volatile cadmium was to be avoided. Indeed, throughout the research this loss of cadmium proved something of a bugbear and was wholly due to the smali scalę of operation; with the larger melts th a t were made in the foundry for investigations of the mechanical properties of similar alloys, no appreciable losses were experienced.

In order to save duplicate chemical analyses of the same materiał,370

FI

GI

.

FI

G.

2 F

IG

when this was reąuired to provide samples for annealing and for thermal curves, the procedure detailed below was followed.

Alloys of Magnesium.— Part I I I

(1) The ingredients were weighed for a 300-grm. melt. The magnesium was melted carefully, a little a t a time, in a stainless-steel crucible, using a fair quantity of the usual magnesium fłux (MgCl2, KC1, CaF2).

371

(2) The aluminium was then added and, when its contents were completely molten, the crucible was removed from the furnace.

(3) When primary crystals were seen to be separating from the liąuid aluminium-magnesium alloy, the cadmium was added and ąuickly stirred in. (By this means the cadmium was added a t as Iow a temperature as was possible. The alternative method of preparation, by melting the cadmium first and adding to it the magnesium and aluminium, was avoided owing to the slowness of the operation.) The addition of the cadmium usually resulted in the previously added flux rising to the top of the melt.

(4) The crucible was returned to the furnace and, when its contents had reached a suitable pouring temperature, a stainless-iron thermal- curve crucible of the type used for the research on the alloys of magnesium and n ickel1 was filled with the alloy, the remainder of which was cast into chill moulds.

(5) The thermal analysis was carried out on the sample, and, when satisfactory curves had been obtained, the materiał was very carefully melted in the thermal-curve crucible under plenty of fłux, taking great care to avoid overheating, and was poured into a horizontal ingot mould.

(6) A vertical slice was cut from this ingot for chemical analysis. The remainder of the ingot was available for heat-treatment. I t was not possible to remove the alloy from the thermal curve crucible without melting, nor was it considered satisfactory to take a sample by drilling the materiał in situ, owing to the possibility of some smali degree of segregation having taken place.

T h e r m a l C u r v e s .

Thermal curves were obtained for alloys containing up to 20 per cent. cadmium on each of the four planes of the ternary diagram representing constant proportions of 5 , 10 , 15, and 20 per cent. aluminium. As mentioned above, the alloys were cast into the crucible on first melting, and covered with flux and with the lid of the crucible. The moving-gradient furnace eąuipment and plotting chronograph were used for making the thermal curves, which were taken a t a ratę of 10 C./minutę. General ly on any one curve only two arrest points were obtamed, but in some instances a smali third arrest, due to flux, was found. The difierence between the temperatures of the liąuidus arrest obtained on heating and on cooling was found to increase with mcreasing cadmium, but in no case was it greater than 8° C.

A test was carried out to ascertain whether any evidence of a difference in composition between top and bottom of an alloy slowly cooled from the liquid could be detected microscopically. A cylin-

372

Haughton and Payne :


drical mild-steel crucible was filled with an alloy containing aluminium 5 and cadmium 10 per cent., and this was treated as though it were a normal thermal-curve sample. The alloy was slowly melted and cooled in the gradient furnace in the same conditions th a t obtained for the cooling-curve specimens. When cold the crucible and contents were sectioned vertically, polished, and etched. On microscopic examination no signs of segregation were detected. Further evidence showing the absence of appreciable segregation in these alloys was obtained when comparative thermal-curves were taken on an alloy containing aluminium 20 and cadmium 20 per cent., (1) in the gradient furnace in the normal manner, (2) in. the apparatus used for thermal analysis of alloys containing a segregating constituent.8 Although the liquidus arrest obtained when using the gradient furnace was less definite than th a t obtained when the latter apparatus was used, the temperatures of the arrest obtained by the two methods were in good agreement. The gradient furnace was used, therefore, for the thermal curves throughout the research.

Heating and cooling curves were taken on one alloy containing aluminium 15-44 and cadmium 4-38 per cent., between the liquidus and 100° C. No arrest was observed below the eutectic. Further reference to these particular curves will be made later.

The results of the thermal curves are shown in Figs. 2-8, the actual yalues obtained being plotted in Figs. 2-5.

T h e L i q u i d u s .

I t will be seen th a t aluminium depresses the liquidus temperature more than cadmium does.

Analysis of the thermal curve alloys after melting out of the crucible showed th a t the actual aluminium content of the alloys agreed with the nominał values to within ± 0-5 per cent. aluminium. This applies to the series containing 5, 10, and 15 per cent. aluminium. The alloys of the series containing 20 per cent. aluminium were not analyzed, as the points obtained for the liquidus arrest fell on a smooth curve.

The liquidus values given by Hanson and Gayler for the binary alloys fali on a smooth curve drawn through the points obtained for the ternary alloys in the case of the 5 and 10 per cent. aluminium sections, while they fali beneath the curve in the case of the 15 and 20 per cent. aluminium sections. This was thought to be due to the lower purity of their alloys and to changes in the accepted values of the melting points of the alloys used for couple standardization. An alloy containing 20 per cent. aluminium, which was made up and subjected to thermal analysis, gave arrest points falling on the curve obtained by extrapolation from the results of the ternary alloys.

A A 3 7 3

Haughton and P ayne:

T h e S o l i d u s .

(1) The Eutectic.—Eutectic temperatures as determined are also plotted in Figs. 2-5. The eSects of the addition of 20 per cent. cad-

374

Fig

s.

6-8

Alloys of Magnesium,.— Part I I I

mium to the aluminium-magnesium alloys is to depress the eutectic arrest by no more than 5° C.

(2) Determination of the remaining surface of the solidus was made by annealings on two series of alloys containing constant 10 per cent. and 20 per cent. cadmium. The annealing of magnesium alloys containing volatile additions a t temperatures between 430° and 600° C. presented some difliculties. At the lower temperatures, and indeed up to about 510° C., it was found possible to anneal samples in air w ithout appreciable loss. Annealings above this temperature were carried out in a bath of magnesium fłux.

The alloys required for solidus determination were given a preliminary annealing a t 420° C. in vacuo for 10 days, to efiect solution of any metastable eutectic th a t might be present.

The samples th a t were to be annealed in air, and a piece of magnesium of equal size were bound together with fine iron wire with the iron-Constantan thermocouple junction between them. They were then suspended in a vertical furnace by means of the binding wire. The sample was held steady a t the required temperature for a period of 10 minutes, after which it was quenched. A layer of metal was removed from the surface of one face of the specimen, and it was then polished and etched in a dilute solution of nitric acid in alcohol. The annealing was repeated a t higher temperatures as required. Fig. 10 (Platę I) shows an alloy containing aluminium 9-44 and cadmium9-32 per cent., which has been annealed a t a temperature about 10° above the solidus.

The annealing of the alloys a t temperatures above 500° C. was carried out w ithout difficulty in the usual magnesium fłux. Flux could not be used as an annealing medium a t lower temperatures owing to its own high melting point.

The results of these quenching experiments are given in Figs. 7 and 8 .

SOLUBILITY OF ALUMINIUM AND CADMIUM IN MAGNESIUM.

(a) Solubility o f Aluminium in Magnesium.—Many workers have determined the solubility of aluminium in magnesium,4* 9> 10’ 11 but the results have to some extent been a t variance. Annealings were then carried out in vacuo a t 420°, 358°, 291°, and 200° C., a preliminary solution treatm ent of 7 days a t 420° C. being given before each precipitation-annealing. The duration of the precipitation-annealing was10 days a t 358° C., 15 days a t 291° C., and 32 days a t 200° C.

The results obtained are given in Fig. 6 . From the eutectic temperature to about 300° C., they are in good agreement with those of

375

Saldau and Zamortin. These investigators, howeyer, had made no determinations of solubility below 250° C., but, from their observations on a slowly-cooled alloy, had concluded th a t there was little change in solubility below 250° C. An alloy containing 3-88 per cent. aluminium was found by the present authors to be duplex on annealing a t 200° C. (Fig. 16, Platę II) a t which temperature the solubility lim it was found to be 2-5 per cent. aluminium lower than th a t given by Saldau and Zamortin, a difference attributable to the short-time annealing given by them to their alloys a t the precipitation temperature.

(b) Solubility of the Aluminium + Cadmium in Magnesium.— Determination of the solubility of the two metals together in magnesium has been carried out microscopically a t 420°, 358°, and 291° C. A preliminary solution treatm ent of 7 days a t 420° C. was given in each case, this period haying previously been found sufficient to establish equilibrium a t this temperature. Ali the above annealings were per- formed in vacuo, the samples being sealed in Pyrex glass tubes.

The curves of solid solubility are given in Fig. 9, and the results were used in the construction of Figs. 3-8.

I t was found th a t homogeneous alloys containing a fair amount of cadmium were ąuickly covered with a tarnish film when placed in any of the ordinary etching reagents. Duplex alloys, however, etched very satisfactorily, the white aluminium-magnesium compound (Al2Mg3) showing up very boldly against the stained solid solution background.* Fig. 11 (Platę I) represents the appearance of an alloy containing aluminium 10-31 and cadmium 8-69 per cent. which has been annealed a t 420° G. and in which only a smali proportion of the Al2Mg3 has been left undissolved. Fig. 12 (Platę I) shows the same alloy when slowly cooled after the solution treatment.

Unless otherwise stated, a dilute solution of nitric acid in alcohol was used for etching all specimens.

M ic r o s t r u c t u r e o f t h e A l l o y s .

Several hyper-eutectic alloys were given the usual solution trea tment a t 420° C. and cooled over some 24 hrs. to room temperatures. On microscopic examination it was noted th a t, in some of the alloys, the Al2Mg3 rejected from solution had not been precipitated in the normal manner shown in Fig. 12 (Platę I), bu t th a t a structure very similar to a eutectoid had been obtained. Fig. 17 (Platę II) shows the appearance of an alloy containing aluminium 15-44 and cadmium4-38 per cent. after this treatm ent. Similar pearlite structures were obtained in alloys containing aluminium 20, cadmium 5 per cent. and

* The constitution of th is compound in the presence of cadm ium has not been investigated, so on the diagrams it has been called y in accordance w ith th e nomen- clature used by Hanson and Gayler.

Haughton and P ayne:

376

f \[POLITECHNIK!! P l a t ę I .

i

^ p-- / > •0

• ■ ■ / 0 ■ r'>/ - 0

_ ° 0

»• /0 O / \ y m

30 ' 4 C "¥ .

; J=S=T ’ 1 1 2 Y 0 j0 %

✓

■ ° i' 1, ■ \ 0 •

#/

. .*

Fig. 10.—Al 9-44, Cd 9-32%. Annealed for10 Minutes a t 480° C. X 500.

F ig . 11.—Al 10-31, Cd 8-69%. Annealed at 420° C. X 150.

F i g . 14.—Al 20, Cd 10%. Annealed a t 420° C. FliV 2° ’. i d . , ^ 0°/“ '1 ^ S,and Slowlv Cooled. Etched with Nitrio Etched wlth Cltrlc Acld ln Alcohol. X 500.Acid in Alcohol. X 500.

377

Platę II .

F i g . 18.-— A l 11-16%. Slowly Cooled to Room F i g . 19.—Al 7-17, Cd 19-51%. Solution at Temperature. X 500. 420° C. Precipitation at 291° C. X 150.

378

F i g . 16.—Al 3-88%. Solution a t 420° C. Precipitation a t 200° C. x 150.

F i g . 17.—Al 15'44, Cd 4-38%. Annealed a t 420° C. and Slowly Cooled to Room Temperature. X 500.


aluminium 15, cadmium 10 per cent., and also in binary alloys in which precipitation had occurred a t Iow temperatures (not above 200° C.) (Fig. 18, P latę II), but it was not obtained in alloys containing large amounts of cadmium, tliougłi in Fig. 19 (Platę II) a form of precipitation intermediate between the “ normal ” and the “ pearlite ” types can be seen. The structure is presumably identical with the “ troostite” structure observed by Ishida in binary magnesium- aluminium alloys. Thinking th a t if this were a genuine eutectoid i t should be possible to detect the arrest point by thermal analysis heating and cooling curves were taken on a piece of unannealed chill- cast bar between temperatures of 100° and 350° C. The materiał

HOMOGENEOUS O OUPLEX O

F ig . 9.—Solid Solubility Isotherms.

used was the same as th a t which showed the “ eutectoid ” after annealing and slow cooling, and, for the thermal curves, was threaded on to a bare thermocouple. No arrest points were detected, so the actual microscope specimen was substituted for the unannealed materiał, and further curves were taken. Again no arrest corresponding to the formation of a eutectoid was found, so the sample was once more polished and re-examined microscopically. Spheroidization of the second constituent appeared to have taken place and no “ pearlite ” was seen (Fig. 13, Platę I).

In order to confirm the absence of any transformation which might give rise to this structure, a sample of the alloy shownin Fig. 18 (Platę II) was placed in a “ capacity ” dilatometer, and a number of heating and cooling curves were taken. The dilatometer was one designed for high- temperature work, and accurate control of the heating and cooling rates a t Iow temperatures was not easy, bu t it can be stated tha t no

379


indication of any transformation was obtained, and it appears, therefore, th a t the structure is probably due solely to the conditions of precipitation. The resnlts obtained may be summed up as follows :

(1) Binary alloys of magnesium and aluminium and alloys containing smali amounts of cadmium, if of suitable composition and if precipitation is carried out a t Iow temperatures, may be obtained with the precipitated compound in a “ pearlite ” condition.

(2) The presence of much cadmium appears to prevent the formation of this structure.

(3) Precipitation a t higher temperatures gives a coarser structure.(4) A spheroidizing treatm ent can be given to the alloys.Further work on these structures is contemplated, in which an

attem pt will be made to correlate them with the mechanical properties of the alloys.

An interesting example of the effects of different etching reagents on one of the alloys is given in Figs. 14 and 15 (Platę I). Fig. 14 shows the appearance of an alloy containing aluminium 20 and cadmium10 per cent. (which had been annealed a t 420° C. and slowly cooled to room temperature), etched with a dilute solution of nitric acid in alcohol. The structure revealed by this treatm ent is suggestive of a “ sheathing ” of the dark constituent by some reaction product formed between the two constituents. When etched with citric acid in alcohol no suggestion of sheathing was apparent (Fig. 15). Further con- firmation th a t no reaction product had been formed is to be found in the fact th a t it was found possible to obtain fringes of varying widths by altering the concentration of the etching reagent used.

Acknowledgments.The authors’ thanks are due to Dr. C. H. Desch, F.R.S., Super-

intendent of the Metallurgy Department, for his interest in the work, toMessrs. W. H. W ithey, B.A.,and P. Ward, B.Sc., of the Chemical Division of the Department for carrying out the analysis, and to Dr. Marie L. Y. Gayler who undertook the dilatometric investigation referred to above.

*R eFERENCES.

1 J . L. Haughton and R . J . M. Payne, J . In s t. M etals, 1934, 54, 275.2 W. E. Prytherch, J . In s t. M etals, 1935, 56, 133.3 W. Hum e-Rothery and S. W. Rowell, J . In s t. M etals, 1927, 38, 137.4 D. Hanson and M. L. V. G ayler,./. In s t. M etals, 1920, 24, 201.5 A. G. C. Gwyer, Z. anorg. Chem., 1908, 57, 113.6 M. Hansen and B. B lum enthal, M etallw irtschaft, 1931, 10, 925.7 J . Yalentin and G. Chaudron, R ev. M et., 1926, 23, 295; and Compt. rend., 1925,

180, 61.8 R . J . M. Payne, J . Sci. Instrum ents, 1934, 11, 90.9 E . Schmid and H. Seliger, Z. Elektrochem., 1931, 37, 447.

10 P. Saldau and M. Zam ortin, J . In s t. M etals, 1932, 48, 221.11 8. Ishida, J . M in in g In s t. Ja p a n , 1930, 46, 245.

380

A Guide to Your Journals!

C O N ^ E N T S

l i s t of itsp u b l ic a t io n s

WITHAUTHOR INDEX

This Contents List, issued in a stiff cover, with an Author Index, will facilitate reference to the papers published in the Journal sińce the Institute’s foundation. It should be found most valuable pending the issue of theio-year Index. Copies are obtainable from the Secretary. Price 2s. 7d. each, post free.

381

AUTHOR INDEX TO AESTRACTSALLISON, F . , 352. A m a r i ,Y ., 347.Ames, O. O., 354. Ananiaschwili, E. G.,

344.Andreae, F . V., 359. Asakawa, Y., 335. Atkins, L. M., 358.

Barattini, A., 350. Bassett, W. H., J r .,

342.Bęchard, C., 349. Beninga, —, 359, 360. Berthold, B ., 355. Betty, B. B., 333. Biggś, H . O., 359. Bihlmaier, K., 352. Bird, P . H ., 343. Blondel, B., 337.Blum, W., 343.Bolton, J . W., 339. Bondy, O., 364.Boone, W. D., 355. Bouchet, L., 346. Bowman, J . J ., 337. Brauer, GL, 343.Braun, A., 349. Bruiltet, A., 354.Bucki ey, H . E., 344. Bullen, F . J ., 346.

Calyet, J ., 333. Carpenter,(Sir)H., 335. Chernysheva, E. Y.,

364.Cook, G., 335.Craig, G. L., 361. C ram er,—, 363. Crampton, D. K., 338. Croft, H . P ., 338.Cutts, V. O., 358.

Dix, E . H., J r ., 337. Dobbins, J . T., 353. Drew, H . D. K., 354. Duczko, K., 341.

Eriksson, S., 343. Evans, G., 360.Evans, S. E., 364.

Fetz, E., 345. Fleetwood, C. W., 351. Forgeng, W. D., 334. Francis, W. B., 360. Frauenthal, A. H ., 360. Freeman, J . B ., J r .,

358.Friederich, E., 342. Frólich, K. W., 353. Fukuda, M., 342.

Gillis, J ., 351.

Glazunoy, A., 348, 350. Goerens, P., 354. Gogoberidse, D. B.,

344.Gorsky, W. S., 338. Gridnev, Y., 338. Grifoll, I., 361. Grosscup, C. G., 353.

Haarich, S., 362. Hallstróm, E., 361. Harada, T., 334. Harnsberger, A. E.,

347.Hasegawa, I., 361. Hauser, F ., 354. H idnert, P ., 333. Hobbs, H. G., 348. Hobrock, B. H ., 362. Hone, A., 342.Honza, B., 350.Honzik, F., 350. Horioka, M., 345. Hukui, S., 355. Humphrey, N. A., 359.

Irion, C. E., 361. Ishida, M., 361.Ishida, S., 341.Itihara, M., 356.Ito , E., 339.

Jakeman, 0., 349. Jensen, B., 364.Jilek, A., 352.Jimeno, E., 361. Johnson, W. C., 353.

Kanao, T., 355.Kasper, C., 343. Kennedy, B. B., 336. Kennedy, T. B., 341. Kenyon, J . N., 355. Kilbum, W. L., 363. Kishino, S., 337. Kodama, M., 335. Korta, —, 363. Koyanagi, K., 343. Krause, H., 361. Krausz, A., 364. Kroenig, W., 346. Kubo, K., 336.Kuno, T., 334. Kurdjumov, G., 338. Kussmann, A., 342. Kyogoku, T., 345.

Laffitte, P., 337.La Que, F .L ., 346,347. Laves, F., 344. Lawrence, B. P., 341. Lee, J . A., 348. Leighton, P. A., 352. Leon, A., 355.

Leonhardt, B . W. P., 355.

Lepingle, M., 359. Leroide, J ., 354.Lewis, E. J ., 354. Liston, J ., 359.Lobley, A. G., 358. Logan, A., 357.Lukens, H . S., 351.

Macarovici,C. G., 354. Mace, C. W., 364. Maekawa, K., 359. Mandran, G., 363. Mason, C. W., 334. Mebane, W. M., 353. Merica, P. D., 341. Misch, L., 338. Mitchell, B. W. 360. Mohr, O 334.Moore, H., 351.Moser, A., 360.Mudge, W. A., 341. Murphy, E. J ., 352.

Nakano, M., 357. Nakata, T., 334. Nishikawa, M., 339. Nishimura, H., 337. Nomiyama, B ., 342. Nusbaum, G. W., 339.

Oettinger, H., 348. Ollard, E . A., 350. Onisi, T., 355.Orowan, E., 344.Otani, B., 340.

Pagel, H . A., 354. Park, B., 354. Partington, E . B., 363. Patterson, W. M., 356. Payloy, S., 346.Petók, Y., 350. Philippot, L., 353. Pliicker,—, 348.Potop, A., 357. Preston, G. W., 338. Pugh, M. D., 357.

Bahn, —, 358.Bandall, J . T., 344. Baub, E., 350. Bedeker, H . E., 352. Bobinson, D. W., 361. Booksby, H . P., 344. Bostomian, P. M., 364. Bowe, W. A., 340. Bussell, A. S., 341.

Sasaki, K., 348.Satd, T., 359.Schied, M., 358. Schneider, A., 343.

Schulze, B., 345. Schulze, F., 363. Schulze, B., 345. Schwarz, F., 362. Seaąuist, E. O., 339. Searle, H. E., 347. Śebor, J ., 353. Sekiguti, Y., 361. Sezawa, K., 336. Shimadzu, S., 334. Shimba, H., 340. Simidu, A., 335, 336. Smekal, A., 344. Snyder, C. J ., 342. Somigli, G., 358. Spacu, G., 354.Spacu, P., 352. Staebler, J ., 363. Sterne, C. M., 347. Sugihara, M., 333. Swamy, Ś. B., 336. Swenden, J ., 351.

Takeuchi, T., 337. Taormina, S. C., 351. Taylor, G. I., 335. Templin, B. L., 356. Theobald, W., 360. Thews, E. B ., 362. Thomas, J . L., 340. Tress, H . J ., 354. Trichś, H., 352.Trinks, W., 360. Troube, F., 333.Tuer, B . S., 349.

Wallace, B . Y., 357. Watase, T., 337.West, O. L., 359. Whitby, L., 346.White, H . Y., 340. Whittemore, H. L., 339. Willstrop, J . W., 347. Wishart, H. B., 355. Wright, T. A., 352. W yatt, G. H., 354.

Varshavski, G., 363. Yartanessov,N.A., 364. Yeith, H . B., 349. • Vernon, W. H. J ., 345. Yreśtól, J ., 352. Yyskocil, A., 346.

Yamaguchi, K ., 336. Yamaguti, K., 364. Yntema, L. F., 351. Yoshida, U., 343. Young, C. B. F., 351. Young, W. W., 358. Yuasa, K., 355.

y. Zeerleder, A., 361. Zintl, E., 343.

382

METALLURGICAL ABSTRACTS(GENERAL AND NON-FERROUS)

Yolume 2 JULY 1935 Part 7

I.— PROPERTIES OF METALS

(Continued from pp. 273-279.)

*Young’s Modulus of Aluminium Rod Composed of Large Crystal Grains.M iyabi Sugihara (M e m . Coli. S c i. K y o to I m p . U n iv ., 1934, [A], 17, 392-396).— [In E nglish.] M etals com posed of large grains a re generally very soft. S. m easured th e Y oung’s m odulus of a lum in ium rods, com posed of c ry sta l gra ins of various sizes, by elongation tes ts a n d b y th e acoustical y ib ra tio n m ethod . T he yalue of Y oung’s m odulus rem ained n early th e sam e irrespective of th e sizes of th e c ry s ta l grains, b u t th e lim it of e lastic ity decreased considerab ly w ith th e g row th of th e c ry sta l g ra ins.— S. G.

High-Grade Aluminium. ------ (M eta llu rg is t (Suppt. to E ng ineer), 1935 ,10,26-28).— A critica l review of a p ap er by Je a n C alvet, C om pt. rend ., 1935, 200, 66 -6 8 ; see M e t. A b s ., th is yolum e, p . 137.— R . G.

*Thermal Expansion o£ Monocrystalline and Polycrystalline Antimony. P e te r H id n e rt (./. R es. N a t. B u r . S ta n d ., 1935, 14, 523-544; R esearch P a p er No. 784).—M easurem ents of th erm al expansion w ere carried o u t on 11 sam ples of single crysta ls of an tim ony an d 3 sam ples of po lycrystalline an tim o n y a t yarious tem p era tu res betw een 20° an d 560° C., a n d th e d a ta w ere correlated w ith th e resu lts ob ta in ed b y previous investiga to rs to 300° C. T he linear expansion depends on th e d irec tion along w hich th e m easurem ents are m ade. F o r exam ple, th e lin ea r expansion along th e trig o n a l axis (0° o rien tatio n ) of a single c ry sta l is a b o u t tw ice as large as th e expansion along a d irec tion p erpendicu lar to th is ax is (90° o rien ta tion ). E q u atio n s were derived w hich show th e re la tionsh ips betw een th e coefis. of expansion a n d th e o rien ta tions of single crystals. T he lin ea r th erm al expansion curves of polycrystalline an tim ony show th a t th ere is no polym orphia tra n sitio n betw een 20° and 560° C. T he diiferences in th e lin ea r expansion of different sam ples of po ly crystalline an tim o n y are a ttr ib u te d to yaria tio n s in th e ayerage o rien ta tio n of th e crystals. A n illu stra tio n com pares th e linear th e rm al expansion of m onocrystalline an d polycrystalline an tim ony .— S. G.

*Metallic Gadolinium. F . T roube (B u li. Soc. ch im . F rance, 1935, [v], 2, 740-742).— P u re gadolinium can be p repared by electrolysis a t 625°-675° C. of a fused m ix tu re of gadolin ium chloride 44, po tassium chloride 44, an d lith iu m chloride 12% , using 7 -8 am p. a t 10 v. w ith a m olten cadm ium c a th o d e ; th e resu lting cadm ium -gadolin ium alloy is d istilled in vacuo a t 450° C. u n til all th e cadm ium is rem oyed, a n d th e residual gadolinium is th en tre a te d a t 1230°-1250° C. in a h igh vacuum to produce a sin tered m ass w hich does n o t oxidize on exposure to a ir an d is n o t a tta ck e d b y boiling w ater.—A. R . P .

*Making and Testing Single Crystals of Lead. B . B . B e tty (A m er . Soc. T est. M a t. P re p r in t, 1935, Ju n e , 1-8).— T he creep oharacteristics w ere deter- m ined fo r specim ens com posed of only one c ry sta l to e lim inate th e effect of m ovem ent a t th e g ra in boundaries, w hich, to g eth e r w ith th e deform ation of th e grains them selves, app ear to determ ine th e creep in po lycrystalline lead. T he m ethod of casting th e crystals, including th e tem p era tu re an d tem pera- tu re g rad ien t con tro l necessary, is described. A n inexpensive, ra p id an d sufliciently accUrate m ethod fo r determ ining th e crystallographic o rien ta tio n of th e .crystals is p resen ted , w hich oby iates th e labour a n d tim e of th e X -ray

* Denotes a paper describing the results of original research. f Denotes a first-class critical reyiew.

A A

334 Metallurgical Abstracts Y o l . 2

m ethod . R esu lts of creep te s ts of 3 specim ens are given. P lanes of slip are identified w ith definite c rystallographic p lanes know n as oc tah ed ra l p lanes.

— S. G.*Estimation o£ the Thickness of the Contamination on the Surface of Metallic

Łead. Shin’ich i Sh im adzu (M e m . Coli. S c i . K y o to I m p . U n iv ., 1934, [A], 17, 79-84).— [In E nglish .] Pow der p h o to g rap h s of surfaces of lead co n tam in a ted by ox id a tio n show ed th a t th e co n tam in a tio n w as com posed m ostly of th e m icroorystals of te trag o n a l lead oxide. B y com paring th e in te n sity of th e d iffraction lines due to th e c o n tam in a tio n a n d th a t of th e lines of th e lead underly ing , th e th ickness of th e co n tam in a tio n w as estim a ted to be betw een 50 a n d 200 ;a}a.— S. G.

The Lead Cable Borer [Insect] in Japan. T akejiro N a k a ta (./. In s t . Teleg . T e lep h . l in g . J a p a n , 1932, (109), 578-589).— [In Jap an ese .]— S. G.

*Total Radiation from Soot-Covered Nickel and from Sand-Blasted Molyb- denum. T suneo H a ra d a ( T o k y o E lect. R e v ., 1932, 7, 11-14 ; J a p . J . E n g . A b s ., 1935, 12, 46).— [In E nglish .] T he effects of sand-b lasting a n d soot- covering in increasing th e to ta l ra d ia tio n from n ickel a n d m olybdenum surfaces w ere in y es tig a ted b y m easuring th e to ta l ra d ia tio n from these surfaces. T he to ta l em issiv ity of soot-covered n ickel is be tw een 0-46 an d 0-85, according to th e th ickness of th e c o a tin g ; th a t of san d -b las ted m olybdenum is be tw een 1-99 a n d 2-36 tim es th e value fo r polished surfaces. T he ran g ę of tem p e ra tu re in y es tig a ted w as be tw een 800° a n d 1100° K . fo r soot- covered n ickel a n d be tw een 1000° a n d 1800° K . fo r sand-b lasted m olybdenum . T he efiect of sand-b lasting is g re a te r a t low er th a n a t h igher tem p era tu res .— S. G.

The Hardness of Single Crystals of Tin. ------- (M eta llu rg is l (Suppt. toE n g in e er), 1934, 9, 178-179).— A critica l su m m ary of a p ap er by E . Schm id, M e ta llw irtsch a ft, 1934, 13, 301; see M e t. A b s ., 1934, 1, 552.— R . G.

*Effect of Bismuth as an Impurity on the Structure and Allotropic Trans- formation of Tin. C. W . M ason a n d W . D . Forgeng (M eta ls a n d A llo y s , 1935, 6, 87-90).— C ast “ C hem pur ” t in , w hen e tch ed w ith a 5 % so lu tion of n itr ic acid in abso lu te alcohol, shows a pecu liar ne tw ork s tru c tu re w hich d isappears on annealing a t 200° C. fo r 50 h rs. a n d reappears a f te r cjuenching o r ra p id cooling of th e m olten m eta l. T in abso lu te ly free from b ism u th fails to show th is phenom enon, w hereas i t reappears o n a d d itio n of a b o u t 0-003% of b ism u th . T he s tru c tu re is a ttr ib u te d to coring, sińce th e solid so lub ility of b ism u th in t in is a b o u t 1% a t room tem p era tu re . T in show ing th e cored s tru c tu re undergoes th e u sua l w h ite — >- grey m odification on cooling, w hereas w hen th is s tru c tu re is rem oved b y annealing an d th e b ism u th is a ll in solid solu tion , th e tran sfo rm a tio n to g rey t in does n o t occur. B ism uth-free t in m ay be m ade b y electro lyzing a so lu tion con ta in ing 250 grm . of stannous chloride c ry sta ls a n d 10 c.c. of n itr ic acid p e r l i t r e ; th e colloidal m etastan n ic acid fo rm ed abso rbs th e b ism u th im p u rity .— A. R . P .

*The Effect of the Oxygen Content on the Electrical Characteristics of Valvular Films of Tungsten, Tantalum, and Niobium. O. M ohr (Z . P h y s ik , 1935, 93, 298-314).— T he e lectro ly tic valve ac tio n of tu n g sten , tan ta lu m , a n d n iobium is in y es tig a ted .— J. 8 . G. T.

On the Emission Characteristics of Tungsten Filaments. T ak u ji K uno (M a tsu d a KenJcyu J ih d , 1933, 8, (1), 4 1 -5 4 ; J a p . J . E n g . A b s ., 1 9 3 5 ,13, 52).—• [In Jap an ese .] T he ripp les of tem p era tu re a n d th e em ission due to th e a.c. h ea tin g of filam ents a re described, as well as th e phase difference betw een th e filam ent yo ltage a n d th e tem p era tu re ripp le . K . also describes a m eth o d fo r ob ta in in g th e em ission ch aracteris tics a t w ide ranges of th e p la te yo ltage an d th a t of th e p la te c u rre n t b y th e cath o d e-ray oscillograph. T he S ch o ttk y effect is considered in p a rticu la r , a n d th e re la tio n betw een th e a rea of th e active surface an d th e shape fa c to r de term ined .— S. G.

1935 I .— Properties of Metals 335tThe “ Single-Crystal ” State o{ Metals. (Sir) H . C. H . C arpen ter (T ra n s .

In s t . M m . M e t., 1933-1934, 43, x li-lx ii).— See M et. Ab-s., 1934, 1, 555.— L M.

The Effect of Fluid-Pressure on the Permanent Deformation o£ Metals by Shear [Copper, Steel]. G ilbert Cook ( In s t . G ivil E n g . Selected E n g . P apers,1934, (170), 1-17).— A ccording to th e m axim um shear-stress an d m axim um shear-s tra in -en erg y hypotheses, applied fluid-pressure should be w ith o u t effect on th e resistance of m etals to p lastic flow; on th e o th er han d , M ohr’s th eo ry re la tin g shear-stress a n d norm al pressure, an d H aigh’s to ta l-s tra in - energy th eo ry oppose th is view . M easurem ents were m ade of th e perm an en t se t of m ild steel a n d copper w hen sub jected to pu re shear in a m edium of glycerine un d er 1 a n d 2500 a tm . K now n values of to rque were applied to th e specim ens, w hich were in th e form of helices, by m eans of ax ia l loading. The steel heliees were annealed a t 900° C. an d th e copper a t 500° C. fo r 20 m inu tes in vacuo. W ith m ild steel, th e p e rm an en t se t below th e y ield -po in t was on th e ayerage inereased 2-5 tim es by a fluid pressure of 2500 a tm . • T his re su lt ind ica tes a lowering of th e p ro p o rtio n a l lim it by pressure, b u t is in only q u a lita tiv e agreem ent w ith th e to ta l-s tra in -en e rg y theo ry . T he y ield -po in t w as n o t affected by pressure. W ith copper, th e resistance to p lastie flow was very sligh tly inereased by pressure, a n d i t ap p ears reasonable to conclude th a t p las tic flow is d e te rm ined to a v e ry elose degree by th e p rincipal shear- stress.— J . C. C.

*A Theory of the Plasticity of Crystals. G. I. T ay lo r (Z . K r is t . , 1934, 89, 375-385).—Cf. M e t. A bs.* 1934, 1, 379. [ In E nglish .] T he experim ental fae ts ind ica te th a t p lastic d is to rtio n u su ah y consists of th e sliding of one p iane of a tom s over its im m edia te ne ighbour so th a t a p e rfec t c ry sta l is reform ed a f te r each ju m p . T . assum es th a t slipping oecurs over lim ited lengths, L , of th e slip-plane giving rise to “ disloeations ” a t th e ends of those leng ths ; th is avoids th e need fo r assum ing large forces to a cc o u n tfo r th e dis- p lacem en t of th e whole slip-plane a t onee. I t is assum ed th a t a t a sufficiently h igh tem p era tu re these d isloeations can m igra te th ro u g h th e c ry sta l under th e sm allest shear-stress, an d in th is w ay a p ic tu re of th e m echanics of p lastic d is to rtio n is ob tained . The th eo ry giyes a parabolic re la tio n betw een stress a n d s tra in , an d th is is confirm ed experim entally fo r m etals w hich crystallize in th e cubic system . The m ig ra tion of th e dislocation is assum ed to be stopped by a n in te rn a l fa u lt surface, a n d in th is w ay th e th eo ry is connected w ith those involving m osaic o r lineage s tru c tu re s ; th e dim ensions of th e blocks ind ica ted by th is th eo ry are of th e o rder 10 cm. in agreem ent w ith th e evidence from o th e r sources.—W . H .-R .

On the Effects of Thermal Stress and Strain on the Process or Mechanism of the Failure of Materials. M otoiti K odam a (J . Soc. M ech . E n q . T o in o , 1933, 36, (192), 261-264).— [In Jap anese .]— S. G.

On the Process and the Mechanism of Failure of Metals. M otoiti K odam a (J . Soc. M ech . E n g . T o kyo , 1933, 36, (193), 315-320).— [In Japanese .]—S. G.

On the Study of the Fatigue of Metals. Y u k iti A sakaw a (J . Soc. M ech . E n g . T o k y o , 1933, 36, (193), 321-322).— [In Jap anese .]— S. G.

*The Process of Creep of Metals. A tum aro S im idu (./. Soc. M ech . E n g . T o kyo , 1933, 36, (189), 7—11; J a p . J . E n g . A b s ., 1935, 13, 5).— [In Japanese .] B y com bining a m echanical lever o r m echano-optical device w ith a ro ta tin g d rum , m ore m in u tę tim e-e lo n g atio n curves fo r steel a n d a lum in ium were ob ta in ed w ith a m agnifleation of deform ation of 100 o r 180 tim es. Sum- m arizing th e results , S. holds th a t creep is n o t a m ere p las tic flow of m etal, as generally expressed, no r is i t a m ere re p e titio n of sudden yielding, depending only on th e te m p e ra tu re ; i t is an a lte rn a te re p e titio n of two k inds of deform atio n .— S. G.

336 Metallurgical A bstracts Yol. 2

*Abnormal Creep o£ Metals and Alloys During Transformation. K eiji Y am aguchi {Buli. I.P .C .R ., Tokyo, 1933, 12, (7), 594-608 ; Jap. -J. Eng. Abs., 1935, 13, 14).— [In Jap an ese .] T he r a te of creep of m eta ls a n d alloys d u rin g cooling a n d h ea tin g increases a b ru p tly w hen th e ir m ic ro stru c tu re changes. T he phenom enon w as recognized fo r t in -b ro n z e , b rass, a n d a lum in ium -zinc alloy in th e case of eu tec to id tran sfo rm a tio n as w ell as in th e secondary separa- tio n o r d isso lu tion of p ro eu tec to id con stitu en ts . T he sam e w as also ex- perieneed in th e g ra p h itiz a tio n of cas t iro n in th e A 1 t ran sfo rm a tio n of eu tecto id steel a n d in th e A 3 tran sfo rm a tio n of iron . S im ilar phenom ena can be seen to a lesser degree in th e tran sfo rm a tio n of [i-brass n e a r 470° C., w hereas a lm ost n o th in g could be seen in th e A 2 change of iro n .—-S. G.

*Relation Between Ordinary "Strength and Creep Strength. A tu m aro S im idu (J. Soe. Mech. Eng. Tokyo, 1933, 36, (200), 831-834; Jap. J . Eng. Abs., 1935, 13, 11).— [In Jap an ese .] P a r t of a generał research on th e creep of m etals. S., who gives a th eo re tica l ex p lan atio n of creep s tre n g th a t h ig h tem p era tu res , describes th e existence a n d m eaning of creep lim it, a n d th e re la tio n as deter- m ined b y exp erim en t betw een o rd in a ry strength. a n d creep s tren g th .—-S. G.

*Measurement of Solid Viscosities of Metals [Aluminium, Duralumin, Copper, Brass] by Means of the Flexural Vibrations of a Bar. K a tu ta d a Sezaw a an d K e i K u b o {Rep. Aeronaut. Res. Inst., Tokyo Im p . Univ., 1933, 7, (89), 195- 231 ; Jap . J . Eng. Abs., 1935, 13, 15).— [In Jap an ese .] D escribes th e experi- m en ta l d e te rm in a tio n of th e coefl. of solid v iscosity fo r a lum in ium , D ura lum in , copper, a n d brass, b y m eans of th e flexural v ib ra tio n of a b a r, th e resistance of a so lid bo d y due to dam ping being assum ed to be p ro p o rtio n a l to th e y iscosity of th e d e fo rm ation of th a t body . I t w as fo u n d th a t th e g rea te r th e am plitudę , th e g rea te r becom es th e coeff. of solid v iscosity .— S. G.

*The Scattering of Light by Thin Metallic Film s. S. R a m a Sw am y {Proc. Indian Acad. Sci., 1934, 1, 347-353).— T he lig h t sc a tte re d b y suffieiently th in films of silver, a lum in ium , a n d t in is fo u n d to ex h ib it th e anom alous d epo lariza tion ch aracteriz ing m etallic surfaces. T h is phenom enon is th u s essen tia lly a surface efEect a n d n o t th e o rd in a ry R ayleigh ty p e of colloidal sca tte rin g . F ilm s th in enough to show th e effect a re fo u n d to ex h ib it no m etallic reflection a n d to hav e a v e ry large e lectrical resistance. I t is suggested t h a t m etallic films have 3 possible d ifferen t s ta te s , viz. a crystalline s ta te w ith m etallic p ro p erties , a tw o-dim ensional gaseous s ta te w hich is n o t m etallic a n d is non-conducting , a n d a n in te rm ed ia te s ta te w ith h igh electrical resistance. A n ev ap o ra ted silver film in th e firs t s ta te sc a tte rs lit t le lig h t; in th e in te rm ed ia te s ta te i t sc a tte rs b rig h t orange yellow lig h t, a n d in th e tw o-dim ensional gaseous s ta te i t sca tte rs b rig h t green lig h t.— J . S. G. T .

II.— PRO PERTIES OF ALLOYS


*Creep Characteristics of Aluminium Alloys. R . R . K ennedy (Amar. Soc. Test. M at. Preprint, 1935, Ju n e , 1-14).— A lum inium alloys a re w idely used in a v a r ie ty of app lications in w hich th e y a re exposed to e levated tem pera tu res . T he sho rt-tim e tensile p rop erties a t these tem p era tu res have been s tu d ied by a n u m b er of investiga to rs , b u t l ittle a tte n tio n has been p a id to th e long-tim e tensile p roperties o r creep characteris tics . N inę a lum in ium alloys th a t have been used o r proposed fo r use a t e lev ated tem p era tu res w ere selected fo r inyestiga tion . T he creep ch aracte ris tics of these alloys w ere de term ined a t 400° a n d 600° F . (205° a n d 315° C.). T he creep ra te s of th e alloys v a ried over a wide rangę. Sand-cast a lum in iu m -co p p er-n ick e l-m ag n esiu m alloy h a d th e b es t creep ch arac te ris tics of th e alloys tes ted . Som e of th e new er w rough t an d c a s t alloys were m arked ly in ferio r to th is alloy in th a t respect, a lth o u g h th e ir

m echanical p roperties a t room tem p era tu re were superior in some oases and th ey have b e tte r casting a n d forging p roperties. A bibliography of 9 refer- enoes is given.— S. G.

*EfEect o! Composition on Mechanical Properties and Corrosion-Resistance of Some Aluminium Alloy Die-Castings. E . H . D ix, J r . , an d J . J . B ow m an (M eta ls Technology, 1935, 2 , A .I.M .M .E. Tech. P ub l. No. 616, 1-12).— See M e t. A b s ., th is yolum e, p . 212.—W . H .-R .

*Hardening Effects of Heat-Treatment on Aldrey-Type Light Alloys. Sakichi K ish ino (N ip p o n K w agalcu K w a i S h i (J . C hem . Soc. J a p a n ) , 1935, 5 6 ,230-235;G. A b s ., 1935, 29, 3283).— [In Japanese .] W hen A ldrey in th e com pletely annealed s ta te is h ea ted above 350° C., its hardness increases. T h is is owing to th e so lu tion of Mg2Si. W hen ąuenched A ldrey is heated , its hardness in creases suddenly a t ab o u t 250° C. owing to th e appearance of Mg2Si crystals. F ro m 250° to 450° C. th e hardness decreases. Above 450° C. th e hardness increases owing to th e so lu tion of Mg2Si. T he d ila ta tio n shows anom alies a t 250° a n d 450° C.— S. G.

*On the Mechanism of the Ageing and Tempering of Quenched Aluminium Alloys. T akeo T akeuchi (.7. M in in g . In s t . J a p a n , 1932, 48, (569), 873-898; J a p . J . E n g . A b s ., 1 9 3 5 ,12, 54).— [In Japanese .] D ila ta tio n , electrical resistance, an d hardness m easurem ents were carried o u t on ąuenched a lum inium alloys con ta in ing copper o r m agnesium a n d Silicon. F rom these experim ents, T . concludes th a t th e solute a tom s in th e su p ersa tu ra ted solid so lu tion are con cen tra ted from place to place p rio r to th e ir p rec ip ita tio n as CuAla or Mg2Si. T h is afEects th e d is to rtio n of th e m other la ttice , an d th e alloy is hardened . T he d is to rtio n will reaoh its lim it, b u t s lig h t h eatin g causes soften- ing b y p rec ip ita tio n of th e com pound. These phenom ena are rep ea ted during th e tem pering an d ageing of ąuenched a lum in ium alloys.— S. G.

*Mechanical and Ageing Properties of Duralumin. Tsuneo W atase (S u iy d - k w a i-S h i, 1932, 7, (38), 424-431; J a p . J . E n g . A b s ., 1935, 12, 55).— [In Jap anese .] A nnealed a n d eold-rolled, a n d aged an d cold-rolled m ateria ls were all hardened w ith increase in th e a m o u n t of cold-w ork. T he m ate ria ł t h a t had been cold-w orked to th e e x te n t of on ly a few % im m edia tely a fte r quenching w as v e ry in ferio r in m echanical p roperties, while th e effects of harden ing were first observed a fte r red u ctio n of 10-12% . A ge-hardening a f te r cold-w ork was s tu d ied b y m easurem ents of hardness an d electrical resistance. H arden ing decreased w ith th e a m o u n t of cold-work. Severe-cold-work, e.g. 5 0 -65% red u ctio n , caused no m ore harden ing a fte r w orking.— S. G.

*Investigation of the Al-Rich A l-F e-S i System. H ideo N ish im ura (T etsu -to - H agane, 1932 ,1 8 ,849-860).— [In Japanese .] See a b s tra c t from E nglish source, M e t. A b s ., th is volum e, p . 147.— S. G.

*The Constitution of the Antim ony-Tin-Zinc Alloys. R o b e rt B londel and P a u l L affitte (C om pt. rend ., 1935, 200, 1472-1474).—T he alloys of th e an ti- m o n y -tin -z in c system have been s tu d ied b y th e rm al analysis, tak ing recognized b in a ry system s as bases. These la t te r w ere yerified by th erm al analysis a n d by m etallography , w hich established a rangę of tin -rich solid solu tions in th e tin -z in c system , a n d confirm ed th e a llo tropic transfo rm ation a t 325° C., a n d th e com pound Sb2Sn3, observed b y Iw asó. T he therm al analysis of th e te rn a ry system was carried o u t in v e rtica l sections parallel to th e b in a ry system tin -z in c , a n d th e resu lts a re inco rpora ted in a piane eąu ilib rium d iagram . T hree te rn a ry peritectics w ere found, p x (an tim ony 0-5, t in 91-5, zinc 8-0% ), p 2 (an tim ony 8, t in 91, zinc 1% ) a n d p 3 (an tim ony 53, t in 40, zinc 7% ), giving rise to 3 transfo rm ations : p 1 : lią u id p 1 + ZnSb c ry sta ls ;== Z n c ry sta ls -|- c c ry sta ls a t 197-5° C .; p 2 : liąu id p 2 + b crystals ^ c c ry sta ls + ZnSb crysta ls a t 235° C .; p 3 \ liąu id p 3 + a c rystals ^ b crystals + c c ry sta ls a t 395° C. T he crysta ls a , b, an d c correspond, respectively, to the b in ary so lu tion lim it a t 95% of an tim ony , th e te rn a ry solu tion lim it a t 42% of an tim o n y (nearly Sb2Sn3), an d th e sum m it y of th e te rn a ry solid solu tion c

1935 I I .— Properties o f Alloys 337


rich m tin . The m elting p o in t of th e peritec tic , p v was fon a d b y differential analysis to be 197-5° C., h igher th a n th a t of th e nearly b in a ry eu tectic S n -Z n (196° C.). T he existence of th e tin -rich te rn a ry solid solu tion , c, w as con- flrm ed by m icro-exam ination a n d electrical-resistance m easurem ents of specim ens annea led a t 150° C. fo r 11 days. T he resu lts seem to show th a t of all th e com pounds of zino a n d an tim ony , on ly ZnSb p lays a n y p a r t in th e te rn a ry system , a n d is conseąuen tly th e on ly one stab le in th e presence of tin .

— J . H . W.*On Two Intermetallic Compounds of Beryllium with Iron. L. Misch

(.N a tu rw iss ., 1935, 23, 287-288).— T he b ery llium -iron system contains a ferro-m agnetio phase FeB e2, th e tran sfo rm atio n p o in t of w hich is 521°-524° C., a n d th e d irec tio n of th e s tro n g est m agnetism in w hich is in th e hexagonal base. T he phase has th e M gZn2 s tru c tu re w ith a = 4-212 a n d c = 6-834 A . ; th e d is 4-65. A second com pound in th is system is FeB e5, w hich is non- m agnetic a t o rd in a ry tem p era tu ro b u t becom es so a t th e tem p era tu re of liąu id a ir. I t h as a b o d y-cen tred cubic s tru c tu re w ith a = 5-878 A. an d d = 3-17.

A, • • —B- B1-Alunum um -Bronze : Its Properties and Applications. ------ - (M eta llu rg ia ,

1935,12, 35-37).-—A d iscussion o n th e com position, m echanical, an d corrosion- resisting p ro p erties of c a s t a n d ho t-w orked “ a lu m in ium -bronzes ” a n d some of th e ir app lications.— J . W . 1).

*The Effect of a Third Element on the Ageing of a Binary System. I.— The System Copper-Aluminium-Nickel. Y. G ridnev a n d G. K u rd iu m o y (D om ez1934, (11-12), 6 1 -6 5 ; G. A b s ., 1935, 29, 3635).— [In R ussian .] T he ad d itio n ° f ^ /o m ckel to th e system co p p er-a lu m in iu m raises th e eu tectic from 570° to 605° C. a n d narrow s th e a-field from 9-8 to 8-6% alum in ium . Below th e eu tec tic no change of so lub ility of n ickel w ith tem p era tu re w as obseryed.

_g QCadmium-Copper for Overhead Lines. G. W . P re s to n (E lec t. R e v ., 1935,

116, 372—373). A brief review of th e m echanical a n d e lectrical p roperties of cad m iu m -co p p er as u sed fo r e lectrical conductors.— S. V . W .

*On Transitions in the CuAu Alloy.— II-III. W . S. G orsky (P h y s ik a l. Z . S o w je tu n io n , 1934, 6, 69-76, 77-81).— [In E nglish .] ( I I .— ) I n co n tin u a tio n of p rev ious w ork (./. I n s t . M e ta ls , 1928, 40, 575), a n accoun t is given of m easurem en ts of th e v e loc ity of tra n s itio n of th e c ry s ta l la ttic e of th e a lloy CuAu to th e eąu ilib riu m s ta te . T he ra tio ci Je of th e c ry s ta l la ttic e is expressed as a fu n c tio n of th e annealing period . No m ath em a tica l fo rm uła capable of expressing th e resu lts w as found . ( I I I .— ) T he effect of s tra in , due to a c h a n ie of th e ax ia l ra tio a /c , o n eąu ilib riu m in th e o rdered la ttic e of th e a lloy I s in v es tig a ted m ath em atica lly .— J . S. G. T.

Wrought Copper-Nickel Alloys. D . K . C ram pton an d H . P . C roft (M eta ls a n d A llo y s , 1935, 6, 79-84).— R ecen t w ork on new n ick e l-copper alloys is review ed, a n d th e p rop erties of th e 92 : 4 : 4 a n d 91 : 7-5 : 1-5 copper -nickel- a lum m ium are discussed. T he m elting p o in ts a re 1090° a n d 1120° C., respec- tiy e ly , a n d th e m echanical p rop erties a re :

9 2 :4 : 4 Alloy. S I : 7-5:1-5 Alloy.

Annealed. Reduced 80%. Quenched. Precipitation-Hardened.

Tensile strength, lb ./in .2 . Yield-point, lb ./in .2 . Elongation, %Reduction in area, % Modulus of elasticity, X 106

45.00020.000

60 80 21

120,00080,000

125018-5

48.00030.000

50 80 21

110,00080,000

103518

1935 I I .— Properties of Alloys 339B o th alloys can be hot-w orked, welded, an d brazed, an d b o th have a good resistance to corrosion.— A. R . P .

*Some Tests on Tin-Bronzes at Elevated Temperatures. J . W . B olton (A m er . Soc. T e s t. M a t. P re p r in t, 1935, Ju n e , 1-9).—The alloy specified in A .S.T.M . S ta n d ard Specifications fo r S team o r V alve Bronze Sand-C astings (B -61), a n essentially solid-solution stru c tu re , is show n to have a “ lim iting creep s tre n g th n of ab o u t 8000 lb ./in .2 a t 500° F . (260° C.) an d to be free from em brittlem en t. A t 600° F . (316° C.), th e alloy has Iow “ c reep-streng th ” and is of Iow d u c tility a f te r exposure to th is tem p era tu re fo r long periods. The alloy specified in A .S.T.M . S ta n d ard Specifications fo r Sand-C astings of the Alloy : Copper 88, T in 8, Zinc 4 % (B -60) (the com position, copper 88, t in 10, zinc 2% , falling w ith in th is specification is th e one specifically referred to), consists of a n essentially solid so lu tion m atrix , th ro u g h o u t w hich a h igh t in com ponent (the a -8 euteoto id) is dispersed in sm ali particles. T h is alloy’s load-carry ing characteris tics a t 500° F . (260° C.) are inferior to those of alloy B -61 , a n d th ere is evidence of em b rittlem en t on exposure to a tem p era tu re of 500° F . (260° C.). M icroscopic s tu d y , especially of m ateria ł exposed to a tem p era tu re of 600° F . (316° C,), shows clearly th a t th is em b rittlem en t is due to p e n e tra tio n o r fo rm ation of th e b rittle euteo to id s tru c tu re along g rain boundaries.— S. G.

*Impact and Static Tensile Properties of Bolts [Steel, Monel Metal, Bronze, Brass]. H e rb ert L . W hittem ore, George W . N usbaum , an d E d g ar O. S eaquist (J . R as. N a t . B u r . S ta n d ., 1935, 14, 139-188; Research P a p er No. 763).— T his in y estiga tion w as carried o u t to determ ine th e p roperties of bolts under im pact tensile loading a n d also u n d e r s ta tic tensile loading. 360 specim ens were tes ted , represen ting all possible com binations of 5 different m ateria ls (chrom- iu m -n ick e l steel, cold-rolled steel, M onel m etal, bronze, a n d brass), 4 different b o lt d iam eters ( f , J , J , § in.), a n d 3 d ifferent form s of screw th read s (A m erican N a tio n a l coarse, A m erican N a tio n a l fine, an d D ardele t). These th read s are o ften used b y U .S. engineers fo r bolts. T he U .S. S ta n d ard th read s are a lm ost th e sam e as th e A m erican N a tio n a l coarse th read s an d th e S.A .E. th read s alm ost th e sam e as th e A m erican N a tio n a l fine th read s. T he bo lts of d ifferent d ia m eters w ere geom etrically sim ilar, th e leng th betw een th e head an d th e bearing face of th e n u t being 5 tim es th e d iam eter, th e th rea d ex tend ing in w ard from th e face of th e n u t 1 d iam eter. I n all cases th e im p ac t w ork for bolts w ith A m erican N a tio n a l coarse th read s w as less th a n for bo lts of th e sam e size and m ate ria ł w ith A m erican N a tio n a l fine th read s. E x ee p t fo r th e b rass bo lts an d those cold-rolled steel bo lts w hich show ed b rittle failures, th e im p ac t w ork for bo lts w ith A m erican N a tio n a l fine th read s w as app ro x im ate ly th e sam e as for bo lts of th e sam e size a n d m ate ria ł w ith D ard e le t th read s. I n all cases th e im p ac t w ork fo r bo lts w ith D ard ele t th read s w as m uch g rea te r th a n fo r bolts of th e sam e size a n d m ate ria ł hav ing A m erican N a tio n a l coarse th reads. S im ilar re la tions were observed fo r th e s ta tic w ork a n d th e m axim um sta tic load. F o r bo lts of th e sam e size an d hav ing th e sam e th read s th e b o lt effl- ciencies w ere app ro x im ate ly th e sam e fo r a ll of th e m ateria ls .— S. G.

*Influence of Iron, Aluminium, and Silicon on the Impact Values of Brasses at Higher Temperatures. M asaichi N ishikaw a a n d E iich i I to (Suiyd/cwai-Shi,1934, 8, 625-629; C . A b s ., 1935, 29, 3283).— [In Japanese .] Brasses were p rep ared con ta in ing 6 2 -65% copper a n d sm ali am o u n ts of im purities of iron , alum in ium , an d Silicon less th a n 1% , an d th e ir C harpy im p ac t values a t h igher tem p era tu res w ere m easured. I ro n d id n o t have a g rea t influence on th e im p ac t value of these brasses, a n d th ey show ed m axim um im pact yalues a t 750°-850° C. according to th e copper con ten t. A lum inium and Silicon, how eyer, h ad a m uch g rea te r effect on th e im p ac t value, and the tem p era tu res show ing th e m axim um im p ac t value were displaced to the low er tem p era tu res 500°-700° C. a n d 450°-650° C., respectiyely , in th e brasses con tain ing a lum in ium an d copper.— S. G.

*Gold-Cobalt Resistance Alloys. Jam es L . T hom as (J. Re-s. N at. Bur. Stand., _ 1935, 14, 589-593; Research Paper No. 789).— G old-cobalt alloys con ta in ing 0-75 to 5 % co b alt w ere p rep ared a n d in y estig a ted to de term ine if th ey a re su itab le fo r use in th e eo n stru ctio n of eleotrioal resistance s tandards . T he tem p era tu re coeff. of e lectrieal resistance of th e alloys con ta in ing 1*5 to2-5% co b alt is sm ali a t room tem p era tu res , b u t th e therm oelectric pow er of th e alloys ag a in st copper is large. T hese alloys w ere fo u n d to be in ferio r to go ld -ch rom ium alloys of a b o u t th e sam e proportions.— S. G.

*A Study of Lead Cable Alloys. H isak ich i S h im ba (Suiyóhai-Shi, 1932, 7, (39), 432-443; Ja p . J . E ng. A bs., 1935, IS , 55).— [In Jap anese .] Tensile a n d bending te s ts w ere carried o u t on age-hardened lead cable alloys conta in in g an tim o n y , t in , a n d ca lc ium ; th e e lectrical a n d fa tigue p roperties were also m easured . L ead a lloys co n ta in ing 1% an tim o n y should be ąuenched a t tem p era tu res above 225° C. fo r age-hardening. Air-cooling also causes harden ing . T he p rop erties of lead alloys con tain ing 0-96% calcium are g rea tly im proved b y ąuenching in oil a t 100° C. from tem p era tu res of m ore th a n 235° C. T he effects of th e ad d itio n of 0 -2 -l-5 % t in to lead alloys con ta in ing 0-04-0-08% calcium w ere exam ined. T he s tre n g th of alloys e x tru d e d a t 255° C. is decreased b y th e ad d itio n of t in ; ageing a t 60° C., how ever, increases th e s tre n g th to 600 k g ./cm .2. A n alloy con ta in ing 1% an tim o n y has superior fa tigue p roperties to one con ta in ing 3 % tin , w hile a lead alloy con ta in ing 0-04% calcium has fa r b e tte r fa tigue p roperties. T en sile s tre n g th a n d e lastic l im it a re m ark ed ly redueed b y long loading, th e lim it being 10% (15 k g ./cm .2) of th e tensile stren g th . T he fa tigue fa ilu re of lead occurs a t th e c ry s ta l boundaries. W ork a n d age-hardening increase th e endurance lim it.— S. G.

*The Surface Tension of Molten Lead Alloys under Oxidizing Conditions.H . V ance W h ite (Metals and Alloys, 1935, 6, 53-56).— T he surface tension of m ono type m eta l con ta in ing lead 76-5, a n tim o n y 16-5, a n d t in 7 % is redueed by 30% b y ad d itio n of 0-05% of sodium an d inereased b y 28% b y ad d itio n of 0-2% of zinc. P o tassiu m a n d cadm ium increase th e surface tension b y a b o u t 4% . A d d itio n of sodium to lead is ju s t as sa tis fac to ry as a d d itio n of arsenie fo r m ak ing spherieal sho t, b u t i t has p rac tica lly no harden ing effect.— A. R . P .

*Bearing Analysis Determines Permissible Speeds. W illiam A. Rowe (Machinę Design, 1935, 7, (1), 30—32).— T he va lue of th e following bearing m eta ls fo r use in cen trifuga l fans has been exam ined : (A) lead 75-7, t in 11-6, an tim o n y 12-2, copper 0 -5 % ; (B) lead 50, t in 38, an tim o n y 11-5, copper 0 -5 % ; (O) t in 89-5, an tim o n y 7-5, copper 3 % . I n a ll cases th e increase in tem p era tu re a t jo u rn a l veloeities (F ) of 10—40 ft./seco n d h as been p lo tte d ag a in st P V , w here P is th e u n it pressure p e r in .2 of p ro jec ted area . W ith F n o t exceeding 20 f t./seco n d A gives th e b es t resu lts , b u t B is sa tis fac to ry u p to V = 30 f t . / second. A t h igher yalues of F th e tin -b ase a lloy C is m uch superio r to th e o thers . T he b es t c rite rio n fo r eva lu a tin g th e perform ance of a bearing m eta l is considered to be th e v a lue of P F 2 fo r a definite rise in tem p era tu re . F o r an increase of 70° F . (39° C.) P F 2 = 9000 fo r A , 24,000 fo r B , an d 18,000 for C. These figures show th a t a lloy B m ay be used as a su b s titu te fo r th e expensive tin -b ase alloys w hen F does n o t exceed 30 ft./second .—A . R . P .

*The Constitution of the Lithium Bismuth Alloys. (Z intl a n d B rau er ) See p . 343.

*The Constitution of the Lithium-Cadmium Alloys. (Z intl an d Schneider.) See p . 343.

*On the Eąuilibrium Diagram of the Magnesium Zine-Tin System. B un-ta ro O tan i (Tetsu-to-Hagane, 1933, 19, (7), 566-572; Jap. J . Eng. Abs., 1935, 13, 62).— [In Jap anese .] T he te m a ry d iag ram of th e m ag n esiu m -z in c -tin system was iny estig a ted by th e rm al a n d m icroscopic analyses. I t w as found

340 Metallurgical Abstracts V o l . 2

1935 I I .— Properties of Alloys 341to consist of 12 p rim ary c ry sta lliza tio n surfaces, 15 u n iy a rian t lines, an d in v a rian t po in ts . T he in v a rian t p o in ts a re sum m arized as follows :

Mg.

Composition.

Zn. Sn.

Temperature,•0.

Rcaction.

2 6 92 175 Liq. = Zn + Sn + e4 88 8 346 Łiq. = Zn -f- e -f- s4-5 87-3 8-2 354 Liq. + y = 5 + e

45 53 2 351 Liq. -f- y = y ' + e46-3 53-2 0-5 340 Liq. = / + € + «46-3 53-2 0-5 340 L iq . = v + y ' + a

— S. G.*Working Properties of Magnesium Alloys. Shiró Ish id a (T etsu-to -H agane,

1932, 18, 705-742; J a p . J . E n g . A b s ., 1935, 12, 52).— [In Japanese .] The cold- a n d hot-w orking properties of alloys of m agnesium w ith a lum in ium and zinc were stud ied . I t is concluded th a t m agnesium alloys should be hot- ro lled a t 300° C., th e tem p era tu re of th e rolls being m ain ta ined a t 250°- 300° C. M agnesium alloys con tain ing up to 7 % alum inium an d m agnesium - zinc alloys w ith u p to 5 % zino can be h o t-ro lled ; th e m axim um lim it of cold-rolling being a red u ctio n of 10% . T he tensile s tre n g th of m agnesium alloys is n o t inereased b y cold-w ork so m uch as h a rd n ess ; elongation an d red u ctio n of a rea a re decreased . T he tem p era tu re of recry sta lliza tio n was found , b y th e X -ray m ethod , to be 170°-200° C.; annealing should be carried o u t a t 300° C. Of th e m etals zinc, m anganese, beryllium , cadm ium , &c., zinc an d m anganese affect th e w orking properties of m agnesium -alum in ium alloys m ore favourab ly th a n th e o thers .— S. G.

*Electrosynthesis of Silver, Tin, and Zinc Amalgams, and Their Chemical Structure. K azim ierz Duczko ( W iadom ości F a rm ., 1934, 61, 633-636, 667- 671, 683-686, 698-700 (700 in G erm an); G. A b s ., 1935, 29, 2859).—The am algam s a re p repared by th e m odified e lectrosyn thetic m eth o d of K erp (Z . E lekłrochem ., 1898, 3, 308) an d by m ixing electro ly tically d ispersed silver w ith m ercury . T he silver am algam s differ in hardness, eleotrical conductiv ity , an d electrode po ten tia l, depending on th e m ethod of p rep ara tion , a n d m u st be regarded , therefore, as d ifferent substances. On th e basis of th e ir m ercury % co n ten t, th e ir volum e changes, specific conductiy ity , electrode po ten tia l, an d photom icrographs, these am algam s are classed as b in ary alloys show ing a crystallographic s tru c tu re an d possessing A gH g as th e sim plest chem ical compound . T in am algam s are crystalline chem ical com pounds of th e form uła Sn7H g w ith a yolum e increase of 8 % ; th ey can ex is t in a n equilibrium w ith free m ercury . Zinc am algam s rep resen t a com m on physical m ix tu re as has been rep o rted b y P u sch in (Z . anorg. G hem ., 1903, 36).— S. G.

*Intermetallic Compounds Formed in Mercury. V.— Compounds in the Zn-M n, Zn-Co, Zn-Ni, A l-F e, Sn-Mn, and Sn-Co Systems. A lexander S. R ussell, T . R . K ennedy , a n d R . P . Law rence (J . C hem . Soc ., 1934, 1750-1754). -—A n u m b er of com pounds, including some new ones, has been fo u n d by th e m ercu ry m ethod . T he em pirical form uła; agree w ith those ob ta in ed by th erm al a n d X -ray s m ethods.— S. V. W .

*Aluminium-Copper-Nickel Alloys of High Tensile Strength Subject to Heat-Treatment. W . A. M udge an d P a u l D . M erica (M eta ls Technology, 1935, 2, A .I.M .M .E . Tech. P ub l. No. 619, 1-12).— A brief descrip tion of th e m echanical p roperties of “ alum inium -M onel m e ta ln m ade by add ing 4 % alum inium to o rd in ary M onel m eta l con tain ing a b o u t 68% n ickel; d a ta

fo r o th e r a lu m in ium -copper-n icke l alloys a re also given. These alloys are so ft a n d duc tile w hen ąuen ch ed from 1200° F . (649° C.) or above, th e m axim um softness occurrm g a f te r ąuench ing a t o r above 1500° F . (815° C.). On slow cooling from tem p era tu res betw een 1200° a n d 2100° F . (649° a n d 1148° C.), th ey becom e h a rd , w ith h igh tensile s tre n g th an d m odera te d u c tility . Tensile s tren g th s of th e o rd er 100,000 to 150,000 lb ./in .2 can be ob tained , w ith e longation values betw een 15 a n d 30% . B o th th e so ft an d th e h a rd form s of th e a lloy a p p ea r as hom ogeneous solid so lu tions w hen exan iined m iero- scopically, a n d th e n a tu rę of th e tran sfo rm a tio n is unknow n. T he corrosion- resistance of th e “ a lum in ium -M onel m eta l ” is sim ila r to , o r sligh tly b e tte r th a n th a t of o rd in a ry M onel m eta l.— W . H .-R .

* Influence o! Stress on the Magnetic Properties of Super-Permalloy. M asaru i u k u d a a n d R y ó ta ró N om iyaina (B u li. T o k y o TJnw. E n g ., 1933, 2, (7), 396- 398; J a p . J . E n g . A b s ., 1935, 13, 43).— [In Japanese .] T he influence of m echam cal stresses on th e pe rm eab ility of iro n alloys of h igh perm eab ility w as in v estig a ted as a m a tte r of technical as well as scientific in te res t. The p ap er also deals w ith th e m agnetic sk in effect of th e alloys.— S. G.

*The Ferrom agnetism of the P latinum -C hrom ium AUoys. E . F riederich a n d A. K u ssm ann (Physikal. Z . , 1935, 36, 185-192).— T he region of composi- t io n w ith m w hich th e p la tin u m —chrom ium alloys a re ferrom agnetic ex tends from 7 to 2 0 % ch ro m iu m ; th e corresponding a tom ic-% of chrom ium are 22— 48’5% . M agnetic sa tu ra tio n in th e case of th e a lloy con ta in ing a b o u t 10% chrom ium (30 a tom ic-% ) corresponds to a fleld -streng th of ab o u t 3000 c.g.s. u n its . M icrographic a n d X -ray investiga tions show th a t crysta lline super- s tru c tu re , based on th e presence of a com pound, ap p aren tly P tC r3, is p resen t m th e fe rrom agnetic alloys a n d ex tends to h igh chrom ium co n ten t, a n d th a t th e fe rrom agnetic rangę is en tire ly a tran s itio n region.— J . S. G. T .

*Reactions in Solid Metallic Systems [Silver-Aluminium Alloys]. A ndre H one ( lte v . tr im est. canad ., 1934, 20, 376-391; C . A b s ., 1935, 29, 3209).— T he v a ria tio n of e lectrical co n d u ctiv ity w ith tim e w as m easured fo r alloys of silver co n ta in ing 38-00, 28-45, 19-85, 11-18, a n d 4-78% alum in ium , a t const. tem p era tu res of 331°, 304°, 265°, a n d 220° C. A m ath em atica l deyelopm ent, based on th e k in e tic th eo ry of gases, is p resen ted to exp la in th e course of decom position of th e alloys. T he “ energies of a c tiv a tio n ” fo r th e reac tio nS -phase----->- y-phase a re fo r th e conditions of tem p era tu re used 22-0, 22-6,25-6, 15-7, a n d 9-3 cal./g rm . m ol., respectively , fo r th e alloys in th e o rder g iven aboye.— S. G.

Special Alloys. ------ (G iessere i-P rax is, 1935, 56, 36, 37, 100, 122).— Seealso M e t. A b s ., 1934,1 , 125, 172, 346,495, 575, a n d th is volum e, p . 219. [N otę :I t seems th a t th is l is t of alloys will con tinue to ap p ea r in a lp h ab etica l o rd e r ; th e c o n tin u a tio n s of th e series w ill n o t be referred to in M e t. A b sĄ The com position a n d som e p rop erties a n d ap p licatio n s a re given fo r : F o rb e’s m eta l F ra ry m eta l, F o n ta n e ’s m eta l, F ra ry l ig h t m eta l, F ricke’s new silver (nickel—brass), F risc h m u t a lum in ium solder, Gedge’s brass, G em m a bearing m eta l, genuine B a b b itt , G erm ania w h ite bronze, G enelit, G lieyor bearing m eta l, go ld -copper, a n d G iusch i-B uisch i.— J . H . W .

342 Metallurgical Abstracts V o l . 2

I I I — STRUCTURE(Metallography; Macrography; Crystal Structure.)

(Oontinued from pp. 284-291.)tPreparation of Łead and Lead-Rich Alloys for Microscopic Examination.

” • H - B asse tt, J r . , a n d C. J . S nyder (M e ta ls a n d A llo y s , 1935, 6, 125-129).— K ecent m ethods fo r p rep arin g sections of lead alloys fo r m icrographic exam ina- t io n a re reyiew ed, a n d th e sphere of usefulness of 8 e tch ing reagen ts is ind icated . C harac teristic pho tom icrographs of num erous alloys a re show n.—A. R . P .

1935 I I I . —Structure 343Mounting Concentrates and Tailings for Microscopic Study. P a u l H . B ird

(E n g . a n d M in . J ., 1935, 136, 233-234).— W hilst m ain ly d irec ted tow ards th e m oun ting of geological specim ens, th e m ethods suggested m ig h t be em ployed in m etallu rg ical w ork. S y n the tie resins, suoh as B akelite , a re used as th e cem enting m edia.— R . Gr.

*Melting of Metal Crystals at Their Boundaries, and a Theory of Recrystal- lization. U saburo Y oshida an d K azuo K oyanag i (M em . Goli. S c i. K yo to I m p . U n iv ., 1935, [A], 18, 9 -16).— [In English.'] I t is found th a t w hen th e te m p e ra tu re of a m eta l is increased to a value ju s t below its m elting p o in t, th e m eta l m elts a t its c ry s ta l boundaries. On th e assum ption th a t th e m eta l m elts a t its c ry sta l boundaries a t its reerysta lliza tion tem pera tu re , a th eo ry of th e reerysta lliza tion of m etals is proposed.— S. G.

The Structure of Metallic Coatings, Films, and Surfaces. —— (M eta l- lu rg is t (Suppt. to E ng in eer), 1935, 10, 22-24).— A review of a G eneral D iscussion held b y th e F a ra d ay S ocie ty ; see M e t. A b s ., th is volum e, pp . 284^-289.

— R . G.*Structure and Properties of Nickel Deposited at High Current Densities.

W illiam B lum an d Charles K asper (M o n th ly R ev . A m e r . E lectroplałers’ Soc., 1935, 22, (5), 19-30).— See M e t. A b s ., th is volum e, p . 287.—A. R . P .

*X-Ray Studies of the System Iron -Chromium Nitrogen. S ten E riksson (Jernkon torets A n n . , 1934, 118, 530-543; C . A b s., 1935, 29, 2829).— Iro n - chrom ium n itrid es were p rep ared b y passing N H 3 over th e hea ted alloys. An in te rm ed iary phase (a ') of th e fo rm uła FeC r w as confirm ed, an d is p robab ly to bo considered a deform ed a la ttice . The sym m etry , however, is low and e ith e r tr i- o r m ono-clinic. I n th e ch ro m iu m -n itro g en system th e hexagonal P-phase has a “ super s tru c tu re ,” w ith a volum e 3 tim es th a t of th e close- p acked hexagonal la ttic e . T he leng th of th e c ax is is th e sam e fo r b o th cells b u t th a t of th e a ax is is 1-732 tim es th a t of th e close-packed la ttice . The hom ogeneity lim its a re 11-9-9-3% nitrogen . T he dim ensions rangę from a = 4-750 A. (2-742 A.), c = 4-429 A. (4-429 A.) an d c /a = 0-933 (1-615) a t the lower lim it to a = 4-796 A. (2-769 A.), c = 4-470 A. (4-470 A.) an d c /a = 0-932 (1-614) a t th e u p p e r lim it, th e num bers in paren theses referring to th e hexagonal close-packed celi.— S. G.

The Alpha-Phase Boundary in the Copper-Tin System. ------ (M eta llu rg ist(Suppt. to E ng in eer), 1935,10, 30-32).—A sum m ary an d discussion of a paper b y T . Isaw a a n d I . O b ina ta o n “ X -R a y In v estig a tio n s on T in-B ronzes,” M etallw irtschaft, 1935, 14, 185-188; see M e t. A b s ., th is Yolume, pp . 56, 289.

—R . G.*The Constitution of the Lithium-Bismuth Alloys. E . Z in tl an d G. B rauer

(Z . E lek trochem ., 1935, 41, 297-303).—In agreem ent w ith th e resu lts of therm al analysis an d co n d u ctiv ity m easurem ents of G rube, Vosskiihler, an d Schlecht,2 stab le in te rm ed ia te phases were fo u n d b y X -ray analysis in th is system a t o rd in ary tem pera tu res . T h ey co n ta in 50 (a-LiBi) a n d 75 a tom ic-% of lith iu m (L i3Bi), a n d have a rangę of hom ogeneity of undetectab le dim ensions. L i3B i is cubic (a = 6-708 A.) w ith 16 a tom s p e r celi; face- cen tred la ttices begin a t 0 0 0 (Bi), U h i i h i i i (Li)- a-L iB i has a te tra - gonal space-cen tred s tru c tu re like th e previously described N aB i, w ith a —3-361 A., c = 4-247 A., c /a = 1-264; B i in 0 0 0, L i in | ł J . The te trag o n a l la ttices of a-L iB i a n d N aB i arise from th e (3-brass la ttic e by d isto rtion , in w hich th e b ism u th a tom s are b ro u g h t to g eth e r in planes parallel to th e basie p iane by m u tu a l co n tac t.— J . H . W .

*The Constitution of the Lithium-Cadmium Alloys. E . Z intl an d A. Schneider (Z . E lek trochem ., 1935, 41, 294r-297).— The existenee of 4 in te rm edia te form s of crysta ls has been found in th e lith ium -cadm ium system by X -ray analysis, in agreem ent w ith th e th erm al analysis an d conductiv ity and d ila tom etric m easurem ents of G rube, Yosskiihler, an d Yogt. One of these

344 Metallurgical A bstracts Y o l . 2phases ((3) ex is ts on ly a t h igher tem p era tu res a n d has possib ly cubic sym m etry . T he fi' phase, w ith rangę of hom ogeneity a b o u t 25 atom ic- % of lith iu m , corresponding to th e fo rm uła L iC d3, has th e m o st closely- paoked hexagonal s tru c tu re (a = 3-083 A., c = 4-889 A., c /a = 1-586, 2 a tom s p e r celi), w ith s ta tic d is trib u tio n . T he m ix tu re-phase (M iseh u n g sstu cke ) betw een (3' a n d cadm ium sa tu ra te d w ith lith iu m (cc-phase) shows tw o d ifferen t ty p es of hexagonaI pack ing , th e ax ia l ra tio of th e one being over 1-8, an d th a t of th e o th e r be ing 1-63 (th e idea ł ra tio of th e closest spherical packing). T he y-phase (LiCd) h as a space-cen tred s tru c tu re of th e N aT l ty p e (a —6-687 A.). A lloys w ith a lith iu m c o n ten t of a b o u t 75 a tom ic-% consist of c ry sta ls (■/') w ith a face-cen tred cubic la ttic e a n d s ta tic a tom ie a rran g em en t (a = 4-250 A .).— J . H . W .

*A M anganese-Silicon Alloy with the Tungsten (A2) Type of Structure. F ritz L aves (Z . K r is t . , 1934, 89, 189-191).— B oren (M e t. A b s ., 1934, 1, 178), who w orked w ith p u re vacuum -d istilled m anganese, fo u n d X -ray evidence fo r th e com pounds M n3Si a n d M nSi, b u t n o t fo r th e ad d itio n a l com pound M n5S i3 claim ed b y Vogel a n d B edarff (M e t. A b s ., 1934,1 , 295), who exam ined less p u re a lloys b y th e rm al a n d m icroscopic m ethods. T he alloys used b y Vogel a n d B edarff have been exam ined b y X -ray c ry s ta l analysis, w hich shows th a t th e M n5Si3 phase of Yogel a n d B edarff is iden tica l in s tru c tu re w ith th e M n3Si phase of B oren , w hich is hexagonal. T he M n3Si phase of Vogel a n d Bedarff has a body-cen tred cubic la ttic e w ith a = 2-85 ± 0-01 A ., a n d a random d istr ib u tio n of a tom s. These discrepancies a re p ro b ab ly due to th e im p u rity (ab o u t 3% , chiefły oxide, iro n , a n d a lum in ium ) in th e alloys of Yogel an d Bedarff.— W . H .-R .

The Naturę of Twinning Planes. E . G. A naniaschw ili a n d D . B . Gogo- beridse (Physilcal. Z . S o w je tu n io n , 1934, 6, 184-185).— [In G erm an.] I t is suggested th a t in th e process of tw inn ing th e c ry s ta l la ttic e is n o t m ateria lly a lte red , a n d th a t v e ry fine crysta lline m ate ria ł is p resen t in in te rstices betw een th e tw ins.— J . S. G. T .t*The Mechanical Properties and the Real Structure of Crystals. E . Orow an

(Z . K r is t . , 1934, 89, 327-343).— T he discrepancies betw een th e theo re tica l an d a c tu a l s tren g th s of c ry sta ls a re described, a n d th e d ifferent theories discussed critica lly . M any exam ples of th e g re a t effect of surface c racks o r flaws are described, a n d i t is show n how w eakness in p las tic defo rm ation can be accoun ted fo r w ith o u t assum ing th e existence of a v e ry deep crack . O. concludes t h a t theo ries of secondary m osaic o r błock s tru c tu re s a re unnecessary, a n d th a t all th e effects can be ascribed to th e presence of flaws.

— W . H .-R .*New Eyidence, Setting an Upper Limit of 500 A. or Less, to Dimensions of

Mosaic Blocks (if Any) in a Crystal. H aro ld E . B uckley (Z . K r is t . , 1934, 89, 4 1 0 ^ 1 5 ) .— [In E nglish .] O ptical in terference effects have been observed fo r lig h t reflected betw een th e opposite p a ralle l faces of m an y crystals, a n d these reąu ire a degree of perfec tion w hich is diflicult to reconcile w ith th e existence of błock stru c tu re s w ith dim ensions of th e o rd er 10,000 A . B . concludes th a t a b łock s tru c tu re is n o t a fu n d am en ta l ch arac te ris tic of a c ry sta l.— W . H .-R .

tThe Theory of Real Crystals. A dolf Sm ekal (Z . K r is t . , 1934, 89, 386-399).-—A review of experim ents on th e s tru c tu re -sen sitiv e p roperties of crysta ls, especially of rock-salts, a n d of S .’s theories of flaws in crysta ls.—W . H .-R .

jSom e Applications of X -R ay Crystallography to Industry. J . T . R an d all andH . P . R ooksby (G .E .C . Jo u rn a l, 1934, 5, 189-196).— T he underly ing principles of th e sub ject a re briefly exp lained , a n d illu stra tio n s a re given of in d u stria l app lications covering such sub jects as th e behav iour of re frac to ry m ateria ls, m anufactu re of glass, w ire-draw ing, rad io valves, a n d h o t cathode discharge tu b es .— S. Y. W .

1935 IV .— Corrosion 345

IV.— CORROSION

(Oontinued from pp. 291-296.)

W hat May Not Be Made W ith Alum inium ? R ich a rd Schulze ( I t .T .A . N a c h r., 1935, 15, (21), 3 -4 ).—P u re a lum in ium m ay be d istingu ished from alum in ium alloys b y d ipp ing th e m eta l in 10—20% caustic soda. I h e con- d itio n s in w hich a lum in ium should n o t be w orked in to tubes, a rm atu res, screw ed jo in ts, &c., because of th e danger of corrosion, are discussed.

— B. BI.tB asic Copper Carbonate and Green Patina. W . H . J . V ernon (•/. C hem .

Soc., 1934, 1853-1859).— S. V. W .*On Hardenable Bronzes on a Nickel-Copper-Tin Base. IV.— Influence ot

Precipitation-Hardening on the Resistance to Corrosion. E . F e tz (K orrosion u . M eta llschu tz, 1935, 11, 100-107).— T he resistance to corrosion of copper- r ich alloys con ta in ing n ickel a n d t in has been de term m ed in 3 % m tn c acid, a n d in 3 a n d 10% hydrochloric acid a f te r d ifferent h ea t-trea tm en ts a n d in conditions of to ta l im m ersion w ith free access of a ir in s ta tio n a ry m edia. T he ra te of d issolu tion of p rec ip ita tion -hardened alloys in n itr ic acid is g reater th e g rea te r is th e a m o u n t of th e new phase p rec ip ita ted in a h igh ly dispersed fo rm ; w ith progressive coagulation of th e disperse phase th e resistance to corrosion approaches th a t of th e annealed m etal. I n 3 % hydrochloric acid th e hard en ed alloys becom e coated w ith a com pact p ro tec tiv e lay er w hich reduces th e ra te of a tta c k below th a t of hom ogenized a llo y s ; a sim ilar eSect is o b ta in ed in 10% hydrochloric acid, b u t th e p ro tec tiy e lay er is n o t so adheren t. T he presence of oxidizing agen ts accelerates corrosion in hydrochloric acid. A nnealed alloys of th e te rn a ry system show approx im ate ly th e sam e resistance to corrosion as th e b in a ry alloy of copper a n d th e p redom inating e lem en t; with. increase in nickel c o n ten t th e resistance to n itr ic acid decreases an d th a t to hydrochloric acid increases. No appreciable de te rio ra tio n of th e m echanical p roperties of th e 7 - 5 : 8 : 86-5 n ick e l-tin -co p p e r alloy occurs a fte r exposure fo r a m o n th to ru nn ing a e ra ted sea-w ater un d er s ta tic loads.— A. R . P .

*The Electrolytic Corrosion of Lead Cable-Sheath. M asaie H orioka and T akao K yogoku (J . I n s t . Teleg. T e lep h . E n g . J a p a n , 1932, (106), 37-57).— [In Jap anese .] See M et. A b s . (-/. In s t . M eta ls), 1933, 53, 21. S. G.

*A Simple Method for Determining the Electrolysis of Lead Cable. M asaie H orioka a n d T akao K yogoku (J . I n s t . Teleg . T eleph . E n g . J a p a n , 1932, (107), 254-257; J a p . J . E n g . A b s ., 1935, 12, 30).— [In Japanese .] Chem ical analyses w ere carried o u t to a scerta in w hether th e corrosion of lead cable-sheath is o r is n o t due to electrolysis, an d also to te s t th e presence of lead p e roside on th e cable surface. Chem ical analysis in th is field is d ifficult. Sm ce m m ost e lectro lysis surveys q u a lita tiv e analysis is sufficient, a very sim ple m ethod w as devised, in w hich a n acetic acid so lu tion of te tram e th y lp -^ -d ia m in o p h e n y l-m e th a n e is po u red over th e lead surface, w hen th e presence of lead peroxide is clearly in d ica ted by a deep blue colour. T he sam e resu lt m ay be o b tained w ith an acetic acid so lu tion of benzid in N H 2-C6H 4-C6H 4-NH2. These solu tions also ind ica te , by colouring, traces of lead ions in th e soil a ro u n d th e concrete duet, th ro u g h w hich th e lead ions ooze o u t b y electrolysis in to th e surrounding soil, th u s rendering i t possible to o b ta in , from outside, a ro u g h idea of electrolysis ol th e cab le-sheath enclosed in th e concrete d u e t.— S. G.

On the Corrosion of Type Metal in Contact with Red Beechwood. -Bruno Schulze (Z . deu t. B uchdrucker verw andte Oewerbe, 1934, 46, 880-881; C hem . Z e n tr ., 1935, 106, I , 786).— T ype m eta l s to red in red beechwood boxes fre- q u en tly becom es soverely corroded, especially if th e boxes a re new. T his is a ttr ib u te d to v apours of volatile organie aeids, p robab ly acetic acid, evolved from th e w ood.—A. R . P .


lp ,w nJ hmTł° n°chnmistl^ °* MełtaUic Magnesium (A Contribution to the Know-lfil 901 ^ n ^ Q MS10nA Antonin VyskociL(ć%m. Listy, 1934, 28, (15- 16), 201-207).—See Met. Abs., 1934, 1, 303.—R. P.11 8S esq?rr0p°in °£ Magnesium- L- Whitby (Korrosion u. Metallschutz, 1935, J ^ agaujst Kroemg and Pavlov (cf. Met. Abs., this yolume,

,, s*atemcnt that hydrogen is evolved from inclusions in mag- W hZ v X T gtCOrr° T is oontradicted by the work of Vernon and w l r l Ł protective action of manganese in magnesium alloys is attributed to the formation of films with a high catliodic oyeryoltage and not to the formation of protective films with a high content of manganese hydroxide.

S. r e ^ H ^f c e7 p h ™ e t . - i . l d P. tŁeir PrCTi0US “ terP-tation of the

Inconel • An Alloy for Textile W et-Processing Eąuipment. F. L La Que(Amer. Dyestuff Reporter, 1935, 24,114-119; C. Abs., 1935, 29,3284).—Inconel contams (approximately) nickel 80, chromium 14, and iron 6%, and is resistant to a very wide yariety of acid and alkali corrosiyes. Mechanical and physical properties of the alloy are tabulated, and also the rates of corrosion in hydro-c f e r , 1? ™ 0’ nitri° a°id SoIutions of strengths! Hypo-

°orroslve to Inoonel than to Monel metal, thoujh it an^stength - S Gm C°ntmU°US C°nta0t Wlth chlorine Meaehing solutions of

*The Properties of Zinc of Exceptional Purity Compared with those of Other Specimens of Zinc. Louis Bouchet (Compt. rend., 1935, 200, 1535- 1537)_

ii®11 made exPerimenta% between the action of redistilied water and chemically pure acid solutions on a specimen of very pure zinc ontammg, accordmg to spectroscopic analysis, not more than 0 -0001°/ of mpurities, with that on other specimens of fineness from commercial

5Ub rf t h 99-995%. , 15% hydrochloric acid: after immersion for’ P^rest zinc lost 2 -2 % of its weight, the loss increasing with

ncfn °t• lmpurlty. UP to 25% for 99-978% zinc ; (2) 20% sulphuricnitrić ad d a W0°n RM T ^ ^ ^ SmaUer 6xtent; (3> c°n“ ntrated +■ * • ^ extra Pure zmo rapidly dissolyed with theeyolution of copious mtrous fumes, while commercial zinc lost only i o fita weight in 10 mmutes; (4) redistilied water (conductiyity = 0-95 xweight = „ £ Pure zinc appeared to increase slightly inweight, but this may haye been due to experimental errors; the othersm a T r^ te n t T r “ f % same. f a™er as (1) and (2), but to a

! actl0n of nltrlc aold can be explained by the tendency of certam impurities to cause passiyity, and by secondary reactions3 H ^ + N H T T ^ tho. f f iatiorl: 9HN03 + 4Zn = 4Zn(N03)2 +

X 5 3’ ? s^ou,ld ,be Possible to estimate the amount of impuritiTs y tłle rate of solution of the metal in the appropriate liquid.

183TlUsm C°rJ 0Si0f- £ ;L RuUel1(Metallurgist (Suppt. to Engi7eer)!\934,' 9 183-186).—Seealso Met. Abs., this yolume, p. 162. Cases of corrosion are

perioration of tubes was attributable to the presence of oil mside. In one case the same type of tube had been used in eondensers

™ iSam/e P?.wer statlon success, and the reason for ita failure in anoil cooler (cooling water mside) was obscure until extraction of the scalę b , t i 6+ l S?J01wed existence of oil. The faulty fitting of the tube

he end-plates liad been mitially responsible for the failures. The effect of a drop of oil settlmg on the tube surface is to set up corrosion by B eren tia l

1935 I V .— Corrosion 347aeration. This was confirmed by laboratory experiments. Similar features were shown by tubes from an oil-tanker, and in the case of failures occurring in motor lifeboats the introduction of oil was traced to the impregnation of the tape with oil prior to packing. Oil was thus present in the water outside the tubes and tended to settle on the top surface. Illustrations of corroded tubes are shown. The detection of oil as the direct cause of tube failures is seldom easy, but it may exist long enough to initiate local corrosion which then proceeds independently.—R. G.

*The Control of Corrosion in Air-Conditioning Eąuipment by Chemical Methods. C. M. Sterne (A m er. Soc. T es t. M a t. P re p r in t, 1935, June, 1-10).—• Corrosion attack of the metallic parts of air-conditioning systems can be so severe that perforation of ferrous sheets and pipes may take place in as short a time as 4 months if the wash water or condenser water is not chemically treated. Practically every type of corrosion attack is common to these systems. Seryice corrosion tests and analyses of the recirculated water show very clearly the causes and degree of seyerity of that attack. The tests also show the degree of protection that may be obtained by proper chemical treatment. S. has carried out corrosion tests in over 200 separate air-conditioning systems, handling both comfort and industrial conditioned spaces in many types of industry and in yarious cities throughout the United States; representative cases are reported in this paper. Check examinations of these systems by the author and others have shown conclusively that by proper chemical treatment and supervision the corrosion attack may be redueed to a minimum.—S. G.

*Propeller Cavitation. Yoshiyuki Amari (Jo u rn a l o f Zosen K io k a i (Soc. N a v a l A r eh. J a p a n ) , 1932, 4 9 ,153-161).—[In Japanese.] After discussing the causes and naturę of the yarious kinds of cavitation of marinę screw propellers, A. describes his own method for dealing with the effect of cayitation on propeller design. The principle of the “ thrust indicator,” which is the most convenient apparatus for the study of the cayitation problem, is explained. Some results of experiments on cayitation are giyen in the appendices to the paper.—S. G.

*The E.M.F. Between Metals in Sea-Water. J. W. Willstrop (A eronau t. R es. Cttee., R . a n d M . No. 1611, 1934, 9 pp. ; and (summary) L ig h t M e ta ls R esearch , 1935, 3, 340-342).—The potentials of yarious metals and alloys against the iV-calomel electrode in sea-water have been determined at 25° and 40° C. 18 : 8 chromium-nickel steel and Monel metal have the most positiye potentials, and these are followed in order by brasses and bronzes, Duralumin, and copper-aluminium alloys, ordinary steels, aluminium alloys free from copper, cadmium, zinc, and magnesium.—A. R. P.

Corrosion-Testing Methods. H. E. Searle and F. L. La Que (A m e r . Soc. T e s t. M a t. P re p r in t, 1935, June, 1-12).—Attention is directed to the practical adyantages of field corrosion tests as an aid in selecting materials to be used in eąuipment that must resist corrosion. A simple and inexpensive device is described that has broad application in field corrosion testing. Based on 8 years of experience in the use of this and other devices, it is considered to be the most practical yet developed. Examples are given to illustrate the accuracy with which performance in seryice has been predicted through its use. I t is suggested that standardization of apparatus for field corrosion testing will be of greater utility than a similar standardization of laboratory testing eąuipment.—S. G.

C O R R O S I O N - R E S I S T A N T M A T E R I A L S .Materials Recommended for Oil-Refinery Pumps. A. E. Harnsberger

(C hem . and, M e t. E n g ., 1935, 42, 144-145).—Bronze is used for casings and impellers of centrifugal reflux pumps in seyere corrosive conditions, and for casing wearing rings, in addition to Monel metal and Stellited steel. Hard,

348 Metallurgical Abslracts Vol. 2

acid-resistant bronze is sometimes used for shaft sleeyes. In the case of centrifugal pumps for absorption plants, leaded-bronze impellers, fitted with Stellited iron rings are used where corrosive conditions are not seyere. Acid- resistant bronze or Monel metal will give fair service on all parts of centrifugal pumps dealing with sludge acid. Acid-resistant bronze or red brass is usually employed for liners and fluid ends of reciprocating acid pumps; bronze and Monel metal for piston-rings, rods, valves and valve seats. Rotary acid pumps usually have acid-resistant bronze cases and shafts or rotors of the same materiał or Monel metal. Sometimes bronze rotors are combined with a Tempalloy shaft. Other pumps may have hard lead cases with Illium rotors and shafts. Bronze parts should be avoided in the presence of caustic soda.

_p j[Corrosion-Resistant] Constraction Materials. James A. Lee (Gherń. and

Met. Łng., 1935, 42, 225—227).—An interesting review of the early discovery and applications of corrosion-resistant materials of eonstruction, with chief reference to the common metals.—P. J.

F.M. Alloy Resistant to Hydrochloric Acid. H . Oettinger (Ind. chim. belge, 1934, [ii], 5, 319).—The alloy (naturę not stated) is said to be practically unattacked by 17% hydrochloric acid or by 4 0 % hydrofluoric acid at 75° C. An elaborate large-scale apparatus constructed of the alloy is illustrated.

—A. E. P.

V — PROTECTION(Other than Electrodeposition.)

(Contmued from pp. 296-298.)

Polishing as a Protection Against Corrosion. ----- Pliicker (R.T.A. Nachr.,1934, 14, (39), 4).—Increase in the corrosion-resistance of metals by polishine is briefly discussed.—B. BI.

Protection of Cables from Electrolytic Corrosion by Means of Low Single Potential Metallic Plates. Koei Sasaki (./. Inst. Teleg. Teleph. Enq. Jamn. 1932, (113), 1056-1079).—[In Japanese.]—S. G.

Zinc Ammonium Chloride. Its Place in Modern Galvanizing. H . G.Hobbs (Iron Age, 1935, 135, (21), 10—13, 84 ; (22), 6, 8, 90).—The history of zinc up to the time of hot-dip galyanizing, the subsequent growth and mechanism of the hot-dip process, and the yarious applications in the galyanizing industry of hydrochloric acid, ammonia, zinc chloride, and sal ammoniac are reviewed. Modern practice is described and the adyantages and disadvan- tages of zinc ammonia chloride as against sal ammoniac and hydrochloric acid are summarized.—J. H. W.

fDeterm ination of the Thickness of Metallic Protectiye Layers. Alexander Glazunoy (Chem. Listy, 1934, 28, 302-305, 313-315).— Methods of determining the value of protectiye metallic coatings are critically reviewed. Two types of coatings are in generał use : (a) in which the coating metal is more electro- positiye, and (b) in which it is more electronegative than the metal base. G.’s method of eyaluating coatings consists in making the coated metal the anodę m a solution of a salt of the coating metal and plotting current density—time curyes, from the steps in which the thickness of the yarious layers can be calculated. In coatings of type (a) the minimum film thickness can also be determined; i.e. an indication obtained of the porosity; this is obtained by adding to the electrolyte an indicator which reacts with the basis metal but not with the plate. The minimum thickness is calculated from the time taken and the eurrent used before a reaction is obtained with the indicator. With porous plates this occurs soon after the beginning of the electrolysis.

—R. P.

1935 V I.— Electrodeposition 349Protecting Machinę Parts by Metal Spraying. H aro ld B. Y eith (M ach inę

D esign , 1935, 7, (2), 28-29).—A brief aooount of th e m eta l spray ing p rocess w ith no tes on th e ch aracte ris tics of sp ray ed coatings is illu s tra ted w ith seyeral exam ples showing th e yalue of such coatings as a p ro tec tio n against corrosion. Spray ing of cast-iron im pellers an d pum p cases, used in iodine m anufactu re , w ith a 0-01 in. coating of Monel m eta l an d a 0-01 in. coating of 6% a n tim o n y -lead alloy prolonged th e life from 6 weeks to 8 m onths. Cheese m ixm g tan k s are sp rayed first w ith zinc, th e n w ith t in .— A. R . P .

Metallizing in Canada. R . S. T u er ( Ir o n S tee l C anada , 1935, 18, 26-27).— T he ad y an tages a n d applications of m etallizing, w hich accoun t fo r th e rap id adyance of th e process in C anada, a re briefly sum m arized.— J . H . W .

Lanolin Rust Preventers. C. Ja k e m a n (D e p t. S c i. In d u s t . R e s ., E n g . Research S p ec ia l R e p . N o. 12, 1934, 26 pp .).— B rig h t steel p a r ts m ay be k e p t free from ru s t du ring storage b y p a in tin g th em w ith a so lu tion con tain ing ab o u t8 lb . of p a rtia lly refined lano lin p e r gali. of w h ite sp ir it o r so lyen t n ap h th a .

—A. R . P .

V I — ELECTRODEPOSITION


Tentative Speeifications for Electrodeposited Coatings of Cadmium on Steel.A non. (M o n th ly R ev . A m e r . E lectroplaters’ Soc., 1935, 22, (5), 7-9).—A m in im um th ickness of 0-0005 in . of cadm ium is speeified fo r generał seryice, and of 0-00015 in . fo r m ild seryice.—A. R . P .

*The Electrodeposition of Alloys of Copper and Tin. Charles B echard (G om pt. ren /l., 1935, 200, 1737—1739).— The m eth o d of depositing a n alloy of p redeter- m ined com position b y m eans of anodes of th e 2 pu re m etals in sh o rt c ircu it (J . In s t . M eta ls, 1933, 53, 446) is n o t applicable to copper—tin alloys. The solutions usually used consist of a m ix tu re of com plex oxala tes of t in and am m onia a n d of copper a n d am m onia, a n d a piece of t in im m ersed in th is so lu tion spontaneously displaces copper, especially if i t is short-c ircu ited w ith copper. A re la tiye ly h igh ou rren t density (5-10 am p ./d m .2) is reąu ired for th e deposition of th e alloy. A lig h t am algam ation of th e t in anodę will regularize th e anodic a tta c k w ith o u t adyersely affecting th e com position of th e b a th o r th e ą u a lity of th e deposit. On th e o th er h an d , th e anodic solu tion of th e copper reąu ires a Iow c u rre n t den sity (0-5 am p ./d m .2), otherw ise th e anodę will d isin tegrate , giying a rough deposit. T he use of bim etallic anodes does n o t fulfil these conditions as in th e case of th e deposition of brass. T hree independen t electric c ircu its are therefore used. The p rincipal c ircu it con ta ins th e cathode on w hich th e alloy is to be deposited an d a n insoluble carbon anodę. T he regeneration of th e b a th is effected by 2 au x ilia ry c ircu its in w hich th e anodę is th e m eta l to be dissolyed (copper o r tin ), th e cathode corresponding to each of these 2 anodes being p laced in a porous p o t filled w ith a so lu tion only evolving hydrogen. T he 3 c ircu its have separa te sources of c u rre n t an d can , therefore, be independen tly controlled. A n «.1k«.lin» b a th of t in (? sod ium ) s ta n n a te a n d po tassium copper cyanide h as also been used, a n d no d isp lacem ent of copper by t in was obseryed, even w hen th e t in was sh o rt-c ircu ited w ith copper, b u t th e anodic a tta c k of th e t in rem ained insuffi- c ien t. To o b ta in a sa tis fac to ry so lu tion of th e t in , p u re m eta l anodes were connected in parallel, a f te r connecting each of th em in series w ith a yariable resistance an d a m illiam m eter, a sim ple cu rren t supp ly being used.—J . H . W .

Brass Electrodeposits for Intermediate Coats. A. B rau n (O berflachentechnik' 1935, 12, 39-42).— B rass undercoatings a re m ore satisfac to ry th a n copper sińce th ey give b e tte r resistance to corrosion an d th e o u ter p la ted coating is m uch sm oother a n d b righ ter. F rom cyanide b a th s ad d itio n of am m onia o r

B B

350 Metallurgical Abstracts Vo l . 2

phenol b righ teners p e rm its b rig h t b rass p la tes to be ob ta in ed over periods of u p to 40 m in u te s ; these adhere well to zinc, iron , t in , and , if th e m eta l is preyiously d ip p ed in a z incate b a th , alum in ium . A finał n ickel p la te affords ad eq u a te p ro tec tio n ag a in st corrosion in a ll cases. T he com position of th e brass p la tin g b a th is discussed a t som e len g th w ith especial reference to th e yalue of b righ teners .—A. R . P .

The Electrodeposition of Chromium. E . A. O llard (M et. I n d . (L o n d .), 1935, 46, 541-542).— T he theo re tica l considerations involved in th e use of a b a th of chrom ie aeid con ta in ing a sm ali ą u a n ti ty of su lphate , th e fo rm ation of su lpha te , th e m echanism of th e reac tion , cathode reactions, an d th e im port- ance of th e su lp h a te co n te n t a re discussed from th e p rac tica l p o in t of view.

x . . . — J . H . W .Crystallization Centres in the Cathodic Deposition of Gold (Electrolysis under

the Microscope.— X). A lexander G lazunoy a n d B . H onza (C hem . Obzor,1934, 9, 124-126).— D eposits ob ta in ed from gold chloride solu tions a re lustrous a n d co m p act so th a t th e ra te of c ry sta llizatio n can n o t be m easured w hen th e n u m b er of c ry sta lliza tio n cen tres is large. A t a h igh cu rre n t d ensity th e deposit is firs t com pact, th e n th e gold is deposited in th e fo rm of a greenish o r red pow der. I n acid so lu tions a v e ry h igh cu rre n t den sity is reąu ired to p roduce pow dery deposits. A dd ition of organie substances favours th e fo rm atio n of com pact, g listening deposits. S im ilar observations have been m ade in th e deposition of pa llad ium from palladous chloride solu tions.— R . P .

Tentatiye Specifications for Electrodeposited Coatings of Nickel and Chromium on Steel. ------ (M o n th ly R ev . A m e r . E lectrodepositors’’ Soc ., 1935, 22, (5),9 -13).— F o r Steel p la tin g tw o grades of deposit a re specified : (a) to w ith stan d th e sa lt-sp ray fo r 48 h rs. th e nn d erco a t should consist of a m inim um thickness of 0-00075 in . of copper a n d n ickel of w hich a t least th e la s t 0-0004 in. is nickel,(b) to w ith s tan d th e sp ray fo r 16 hrs. th e m in im um thickness of th e un d erco a t should be 0-0004 in . of w hich th e la s t 0-0002 in . is nickel. I n b o th cases th e finał chrom ium co a t should be a t least 0-00002 in. th ick .—A. R . P .

The Influence of Additions to the Nickel B ath on the Deleterious Effect of Iro n Therein. E . R au b (M itt . F orschungsinst. E delm eta tte , 1935, 9, 1-8).— E ssen tia lly th e sam e as a p ap er by R au b a n d W alter, Z . E lek trochem ., 1935, 41, 169; cf. M e t. A b s ., th is volum e, p. 237.— A. R . P .

D eterm ination of the Thickness of the Deposit on Nickel Plated W ires by G lazunov’s Method. V. P ę ta k an d F . H onzlk (C hem . Obzor, 1934, 9, 104-107). — E lectrodeposits consist of a lay e r of th e p la te d m eta l above a th in lay er of a n alloy of th is m eta l w ith th e basis m eta l p roduced by diffusion. T he th ic k ness of these layers can be de term ined , according to G lazunoy, b y anodic d issolution an d o bservation of th e p o ten tia l an d c u rre n t density , w hich rem ain c o n s tan t u n til th e o u te r lay e r h as com pletely dissolyed an d th en change con- s is ten tly u n til th e basis m eta l is reached . F ro m th e cu rre n t den sity an d tim e of d isso lu tion a t each stage th e th ickness of th e 2 layers can be calculated . Good resu lts a re o b ta in ed on n ickel-p la ted copper.— R . P .

Nickel Anodes. A. B a ra ttin i ( In d u s tr ia m eccanica , 1935,17, 9 -1 2 ; C. A b s .,1935, 29, 3239). T he p o in ts of view w hich should de term ine th e selection of n ickel anodes are discussed. C ast anodes, even if sufficiently pure , have a low efficiency, because th e y d isin teg ra te irregu larly on accoun t of th e ir po ro sity an d leaye undissolyed m uch non-recoverable scrap. B righ t, rolled alloys a re also n o t v e ry su itab le , as th ey becom e passiye read ily . A nnealed rolled alloys w ith m echam cally roughened surfaces go in to so lu tion un iform ly an d give a m uch h igher anodę efficiency th a n th e 2 ty p es of anodę m entioned aboye. T hey are su itab le fo r co n cen tra ted b a th s w ith m edium c u rre n t density . A nodes c u t from nickel-refinery cathodes a re seryiceable p rov ided th a t th e Cl“ c o n ten t of th e b a th is reg u la ted . Cl” ad d itio n is recom m ended fo r a ll anodes in operating w ith h igh an d m edium cu rren t densities.— S. G.

1935 V II .— Eledrometallurgy and Eledrochemistry 351Silver Plating to Specifications. C. B. F. Young and S. C. Taormina (Met.

Ind. (N.Y.), 1935, 33, 165-167).—The results of experiments are cited which show that silyer can be plated to specification provided that the solution is maintained to a standard by periodic analysis, the work is distributed as regularly as possible with respect to the anodes, similarly shaped and sized articles are plated together, and the current density is regulated by means of a pilot. Allowance must be made for the amount of silver removed in the finał bufiing operation; this averages, for well-plated articles, about 10% of the total amount deposited.—A. B. P.

*Electrodeposition o£ Siiver from Iodide Solutions. Charles W. Fleetwood and L. F. Yntema (Indust. and Eng. Chern., 1935,27,340-342).—A quantitative study of a bath containing citric acid 60 and sodium iodide 520 grm./litre, using a silver anodę, showed that the deposit is fine-grained and adherent. No quantitative study was made of the throwing power, but there appeared to be uniform deposition even on irregularly-shaped articles. The permanency of the bath is indicated by the fact that it gave as good deposits after standing exposed to the atmosphere for 4 months as when newly prepared. The anodę corrosion is good. When operated at cathode efficiencies of 80% and higher, the silver content of the bath is increased. The bath is easily prepared.—F. J.

Tentative Specifications for Electrodeposited Coatings of Zinc on Steel.----- (Monthly Rev. Amer. Elecłroplaters’ Soc., 1935, 22, (5), 4-6).—For generałservice the minimum thickness of zinc shall be 0-0005 in. and for mild serńce 0-00015 in.—A. R. P.

The Electro-Deposition of Metals. H. Moore (Metallurgist (Suppt. to Engineer), 1934, 9, 191-192).—A brief survey of the organization of research work on electrodeposition carried out in Great Britain, and a description of some of the results of work on pitting, adhesion, and properties of electrodeposits. Recent changes in control of the researches, and the need for further work for which the support of industry is necessary, are discussed.

—R. G.

VII.— EŁECTROMETALLURGY AND ELECTROCHEMISTRY(Other than Electrodeposition.)

(Oontinued from p. 302.)

*Researehes on the Electrolysis of Metals During the Simultaneous Scraping of Anodę and Cathode by a Diamond. J. Gillis and J. Swenden (Rec. trav. chim., 1935, 54, 219-234).—The electrodes used were 2 wires, arranged so as to be scraped simultaneously by a diamond. It was found that with Iow concentrations of normal salts of copper, nickel, cadmium, and mercury, using scraped electrodes of the same metal (dropping electrodes for mercury), there is a straight-line relation between the potential difference and the current density. For copper and nickel the straight-line relation gives place to a logarithmic curve above a certain concentration of the bath. For all the straight-line curves the relation between the polarographic resistance r and the concentration c is given by : log / = a + b log c. The factor/ is the ratio of the polarographic resistance to the resistance of the electrolyte; its value is smali for metals of Iow polarization, and high for metals of high polarization.

—C. E. H.*Mechanism of Conductance. Hiram S. Lukens (Electrochem. Soc. Preprint,

1935, Mar., 317-324).—Lines of equipotential in the solution between 2 electrodes of the same and of differing contour have been mapped out by a new method involving the use of an exploratory auxiliary electrode. The results show that whenever 2 electrodes in contact with an electrolyte are polarized

352 Metallurgical Abstracts V o l . 2the electrie field established produces a state of stress which is characterized by a potential drop between all parts of the electrolyte and the electrodes. The bearing of this on accepted theories of conductance is briefly diseussed.

—A. R. P. '

IX .— ANALYSIS

(Continued from pp. 303-305.)The Role o£ the Spectrograph and of Minor Elements in Die-Castings.

Thomas A. Wright (Metals Technology, 1935, 2, A.I.M.M.E. Tech. Pnbl. No. 614, 1-9).—W. refers briefly to the effects of some impurities in Al, Zn, white metal, Mg, and brass alloys used for die-castings, and indicates possible sources of contamination, and the advantages of spectrographic analysis.

, —W. H.-R.Quantitative Spectrographic Analysis of Calcium and Barium in Light

Alloys and Solutions, and Various Influences on the Emission of Rays. Henri Tnehó (Compł. rend., 1935, 200, 1665—1667).—An account of investigations under the auspices of the Service techniąue et des Kecherches de 1 Aóronautique. Equal intensity of the lines 3933*67 Ca+ and 3891-78 Ba+, using a gold or, better, pure aluminium electrode, is obtained with a weight

°’ Ca = 1 This method £ives Ca to iijoo in alloys and iooWo in solutions. Por greater rapidity and absolute sensitiyity, a spark is passed between an alloy containing Ca and a solution containing only BaCl2. This method has the advantage of not destroying the alloy, but the conditions are well-defined. Taking the intensity of the Ca line as unity, the intensity of the Ba line has been studied as a function of (1) the temperature of the solution, to which it is proportional between 0°-60° C., a rise of 5° C. producing an increase of intensity of 10%, (2) the concentration of HC1—the intensity increases initially in proportion to the number of drops introduced into the solution, and then more slowly until the chloride becomes insoluble. The intensity increases eąually with the current in the primary of the transformer, but all measurements were, in fact, made with a oonstant current. These results can be explained by the increase of the conductivity of the solution and thus by that of the spark, and probably by the lowering of the surface tension. Surface tension appears to play a comples part in the mechanism, and its action was inyestigated by adding to the solution yarious active organie substances which liad little effect on the conductiyity of the solution. A method of rapidly obtaining eąuality of intensity is described.—J. H. W.

Possible Use of the Poulsen Arc as a Means of Detecting Traces of Impurities in Metals. Harry E. Redeker and Philip A. Leighton (./. Amer. Chem. Soc., 1930, 52, 4169-4170).—A letter.—I. M.

*A Magneto-Optic Method of Chemical Analysis. Fred Allison and Edgar J. Murphy (./. Amer. Chem. Soc., 1930, 52, 3796-3806).—See J. Inst. Metals, 1930, 43, 540.—I. M.

The Recognition of Platinum and Palladium and the Distinction of Platinum, Palladium, and W hite Gold Alloys from Base Metal Alloys Resembling Platinum. Karl Bihlmaier (Mitt. Forschungsinst. Edelmetalle, 1935, 8, 131— 137).- Physical and chemical tests for P t and Pd in alloys, residues, and solutions are described briefly.—A. R. P.

*Separation of Aluminium from Nickel and Cobalt by Means of Hydrazine Carbonate. A. Jilek and J. Yreśtal (Chem. Listy, 1934, 28 ,113-115).— Double precipitation of the Al with N2H4-H2C03 seryes to effect or complete separation from Ni and Co. Ignition of the precipitate affords pure A120 3.—R. P.

*Method for Separating Iron and Cobalt Quantitatively. Pierre Spacu (Compt. rend,., 1935, 200, 1595-1597).—To the hot neutral or feebly acid solu-

1935 I X .— Analysis 353tion of the 2 met,ais (the Fe being oxidized by boiling with a few drops of HN03, if necessary), pyridine is added drop by drop unt.il all the Fe is precipitated and the solution remains elear, 3-4 drops in excess being added. The precipitate is filtered, washed with hot water, ignited and weighed as Fe20 3. To ensure that the Fe(OH)3 has not adsorbed traces of Co, it can be redis- solyed in HC1 and reprecipitated with pyridine. The Co can be determined in the solution direct in the form of the aminę, CoPy4(SCN)2, by the method described by G. Spaou (J. Inst. Metals, 1927, 38, 510).—J. H. W.

*EIectrolytic Determination of Cadmium. Jan Sebor (Chem. Listy, 1934, 28, 290—291, 297—299). Quantitative deposition of cadmium as a bright plate is obtained from a stirred eleotrolyte containing K2C20412, CH3-C02Na 3 grm., and 20% CH3-C02H 3 c.c. in 120 c.c. of water using a current of 0'2 amp. at 2-9 v. a t 70°-80° C. Up to 0-16 grm. of Cd can thus be deposited, and up to 0-24 grm. if 0-25 grm. of C6H5OH is added to the electrolyte. In the latter case the deposit becomes crystalline, the time of deposition is trebled, and the solution becomes brown owing to formation of ąuinone. Using a current of 0-1 amp. Cd can be separated completely from Zn.—R. P.

*A Study of the Quantitative Precipitation of Calcium Oxalate in the Presence of the Arsenate łon . J. T. Dobbins and W. M. Mebane (J . Amer. Chem. Soc., 1930, 52, 4285-4288).—See also J. Inst. Metals, 1930, 44, 579. Accurate results may be obtained as follows : make the solution alkaline with NH4OH and add a few drops in excess. Add excess (NH4)2C204 to the boiling solution and keep this at incipient boiling temperature for 10 minutes with occasional stirring. After standing for 1 hr., filter off the precipitate, wash with distilled water containing a smali amount of NH4OH, transfer on the paper to the precipitation beaker, dissolve in 30 c.c. dilute H2S04, dilute to 100 c.c., and titrate rapidly with 0*lA7-KMn04 solution. The best temperature for precipitation is 90°-100° C.—I. M.

Determination of Cobalt by Means of a-Nitroso-[3-Naphthol. Lśon Philippot (Buli. Soc. chim. Belg., 1935, 44, 140-153).—To avoid the usual difHculties in igmting the Co-naphthol precipitate P. recommends digesting it with fuming HN03, evaporating the solution with H2S04, diluting and precipitating the Co with KOH and Br; the Co(OH)3 is then dissolved in H2S04 and H202, and determined by electrolysis.—A. R. P.

*Studies on Heteropoly Acids of Germanium. I.— Germanomolybdic Acid Charles G. Grosscup (J. Amer. Chem. Soc., 1930, 52, 5154-5160).—It is suggested that a new acid, H8[Ge(Mo20 7)6] aq., and its salts may be used for the colorimetric determination of Ge.—I. M.

*Nitrogen Compounds of Germanium. I — The Preparation and Properties of Germanie Nitride. Warren C. Johnson (./. Amer. Chem. Soc., 1930, 52, 5160-5165).—Ge3N4 is readily reduced by H2 at 700° C. according to the eąuation Ge3N4 + 6H2 = 3Ge + 4NH3, and this reaction may be used for the analysis of Ge.—I. M.

*Sulphuric Aeid Attack on Platinum-Gold Silver Alloys and Its Importance in Cupellation (die Dokimasie). K. W. Frolich (Z. Elektrochem., 1935, 41, 207-211).—I t is shown that the usual cupellation (dokimatischen) determination of Au and P t is not sufficiently accurate. Errors in analysis are caused by the fact that boiling H2S04 can dissolve appreciable amounts of Pt as well as sonie Au. Although P t is more resistant to concentrated H2S04 than Au at lower temperatures, at temperatures over 260° C. it becomes in- creasingly less resistant. A method of analysis is described which, by making use of the selective reducibility of As-", reduces the limit,s of error to from i to for gold and from to -Ą for P t of the errors by the older method. Using a solution in H2S04 corresponding to 0-5% of As and a P t : Au ratio of not more than 1: 10, the errors amount to about ±0-3 per thousand for Au and ± 3-0 per thousand for Pt.—J. H. W.

354 Metallurgical A bstracłs V o l . 2

*Estimation of Smali Amounts of Lead in Copper. Bartholow Park and E. J. Lewis (Indust. and Eng. Chem. (A nalyt. Edn.), 1935, 7, 182-183).—In the determination of traces of Pb in Cu by the spectrographic method a preliminary concentration of the Pb is necessary; this may be effected by dis- sohdng 50 grm. of the Cu in HN03, adding a slight excess of NH4OH followed by 2 c.c. of 50% NaH2P 04 solution and 50 c.c. of 1 : 2.\ H4OK saturated with C02, and collecting the Pb3(P04)2 precipitate by adding an excess of CaCl2 solution to precipitate a mixture of Ca3(P04)2 and CaC03. The mixed precipitate is collected, washed, and dissolyed in HC1, the Pb and a smali amount of Cu are precipitated with H2S, and the sulphides are dissolved in HN03 to give 5 c.c. of solution for spectrographing after absorption in a carbon electrode. The method will detect 6 X 10-7 grm. of Pb using the Pb line at 2833 A. and comparing this with that given by a series of standards.—A. R. P.

Note on the Volumetric Determination of Manganese. J. Leroide and A. Bruiltet (Buli. Soc. chim. France, 1935, (v), 2, 740-742).—In the Volhard method of determining Mn by titrating the hot neutral MnS04 solution with KMn04 the addition of ZnO is unnecessary if a large ąuantity of Na2S04 or K2S04 is added to the solution. Much Ee or the presence of Cl/ interferes with the titration.—A. R. P.

*The Micro-Determination of Platinum and Iridium, and of Associated Chlorine and Potassium. H. D. K. Drew, H. J. Tress, and G. H. Wyatt (./. Chem. Soc., 1934, 1787-1790).—S. V. W.

*A New Volumetric Method for the Indirect Determination of Zinc. G. Spacu and C. Gh. Macaroyici (Bul. Soc. Stiinte Clwj, 1934, 8, 129-139; Chem. Zentr., 1935, 106, I, 1422-1423).—The method depends on the precipitation of the Zn by addition of a known yolume of 0-lA-NH4CNS solution and C5H5N, filtration of an aliquot part of the solution, and titration of the excess of NH4CNS with AgN03 after neutralization of the solution with HNOs.

—A. R. P.*The Iodimetric Determination of Smali Amounts of Zinc. H. Armin

Pagel and 01iver C. Ames (J. Amer. Chem. Soc., 1930, 52, 3093-3098.—The iodimetric determination of smali amounts of Zn, precipitated as zinc pyridine thiocyanate, has been developed. Data and the details of the procedure and technique are given.—I. M.

X .— LABORATORY A PPA R A T U S, INSTRUMENTS, &c.(See also “ Testing ” and “ Temperature Measurement and Control.” )

(Continued from p. 305.)

On the Recent Development of Microscopy with Reflected Light. F.Hauser (R .T .A . Nachr., 1934, 14, (30), 3).—A microscope with various illuminating devices is described.—B. BI.

A Device for Measuring Irregular Areas. ------ (Eng. and M in . J ., 1935,136, (5), 259).—Describes an instrument based on the strip method of area determination. It consists of a transparent disc inscribed with a series of concentric circles calibrated in units of area.—R. Gr.

XI.— PHYSICAL AND MECHANICAL TESTING, INSPECTION, AND RADIOLOGY


Ideas on the Standardization of Testing Methods. P. Goerens (R .T .A . Nachr., 1934, 14, (42), 1).—Points of view for an international standardization of methods of materiał testing are discussed.—B. BI.

1935 X I .— Physical and Mechanical Testing, &c. 355The Inspection oJ Die-Castings. R. W. P. Leonhardt (Met. Ind. (Lond.),

1935, 46, 617-619).—The speotrographic and chemical analysis, shop-testing, X-ray and micrographic analysis, and the corrosion-resistance testing of die- castings are deseribed.—J. H. W.

fPosition and Development of Non-Destructive Materiał Testing. R. Bert- hold (Z.Y.d.I., 1935, 79, 477-484).—The principles of and apparatus for inyestigating the fine structure of metals with X-rays and various magnetic testing methods are deseribed, and details are given of the filing and turning methods of examining metals.—K. S.

*A New Method for Investigating Solid Elastic Strains by Using Agar Jelly. Tadayosi Kanao (J. Soc. Mech. Eng. Tokyo, 1933, 36, (195), 453—459; Jap. J. Eng. Ais., 1935, 13, 8).—[In Japanese.j A study of yolume strain, using specimens of agar jelly mixed with powdered graphite.—S. G.

*0n Optical Creep in Photo-Elastic Phenomenon. Kameiti Yua3a, Sinzi Hukui, and Tadasi Onisi (./. Soc. Mech. Eng. Tokyo, 1933, 36, (195), 447^52; Jap. J. Eng. Abs., 1935, 13, 8).—[In Japanese.] An investigation of the time effect of the optical and strain creep of phenolite and celluloid tension specimens. The photo-elastic const. of phenolite is a function of time, and there are two different yalues for given stresses, it yaries very ąuickly right after loading. There is no simple relation between optical and strain creep.—S. G.

*The Rotating-W ire Arc Fatigue Machinę for Testing Small-Diameter Wire. J. N. Kenyon (Amer. Soc. Test. Mat. Preprint, 1935, June, 1-9).—A stress- reversal machinę developed on the principle of a rotating wire bent to arc curvature is being used to test small-diameter wire. Resonant yibrations or standing waves are damped in an oil-bath. The specimen automatieally assumes the form of a circular arc by the elimination of flexural shear. Test results so far obtained give satisfactory yalues for small-diameter wire.

—S. G.*High-Speed Fatigue Tests of Several Ferrous and Non-Ferrous Metals

[Duralumin ; Brass] at Low Temperatures. W. D. Boone and H. B. Wishart (Amer. Soc. Test. Mat. Preprint, 1935, June, 1-6).—The authors present a group of low-temperature high-speed fatigue tests. Two cantilever fatigue machines, deyeloped at the Uniyersity of Illinois, using 12,000 r.p.m. series motors, were used in the tests. A description is given of the machines and their operation at temperatures that yaried from -f- 80° to — 55° F. (27° to— 48° C.). Two types of smali inexpensive specimens were tested. Unnotched specimens were used to give maximum endurance limits for the materials, while notehed specimens were used to show the effect of stress concentration. Endurance limits of Duralumin, brass, grey cast iron, meehanite cast iron, cold- drawn steel, and raił steel were determined for unnotched and notehed fatigue specimens for temperatures of + 80°, + 10°, — 20°, and — 40° F. (27°, — 12°,— 29°, and — 40° C.). In generał, as the temperature was decreased the endurance limits of the metals inereased. The stress concentration factors showed no consistent change.—S. G.

*On the Róle of Separating Fracture [Trennungsbruch] in the Light of Mohr’s Strain Hypothesis. A. Leon (Bauingenieur, 1934, 15, 318-321).— Aecording to generał opinion, MohrJs theory is applicable only to shear fracture. For separating fracture, which should be excluded from the theory, experiments have shown that the resistance to separation remains constant irrespectiye of whether the state of stress is linear, planar, or spatial, which corresponds with the theory of normal principal stress, which, therefore, ought to be utilized to amplify Mohr’s theory for the case of separation fracture. Really, however, Mohr’s theory coyers separation fracture and the phrase constancy of resistance to separation, the shape of the sheath lines (Hiill lines) giying an indieation of the circumstances in which separation or shear fracture will occur.—B. BI.

*Impact Torsion Tests (Ho. 2). I . - 1 7 0 0 r.p.m. Impact Torsion Tester. 5 ;' „ pa? a"d Statl? Torsion Diagrams o£ Metals at Room Temperature. 5f: Con^deraticns oJ the Dynamie Sliding Resistance of Metals. Mititosi itihara (Tech. Hep. Tóhoku Imp. Univ., 1935,11, 489-1-90, 490-504, 505-511 • and Japanese) Trans. Soc. Mech. Eng. Japcm, 1935, 1, 20-27).’

i aPPara us» in which the twisting moment andangle of twist are recorded photographically, is briefly described with reference to a photograph and diagram. (II.—) The impact and static torsion diagrams of brass, tin, lead, copper, aluminium, zinc, and Duralumin haye been constructed and compared with those of various ferrous metals. For face-centred cubic metals the 2 curves are almost coincident, whereas for body-centred cubic metals, e.g. iron, the angle of twist in the impact test is about 10- 20% greater than that m the static test and the yield-point is about 3 times as

' 7 7 , , dynamic slidmg resistance of a metal is shown to consistot the sum of the elastic resistance and the yiscous resistance. The shape of the impact diagram of body-centred cubic metals is attributed to the decrease of elastic resistance and coeff. of viscosity when the specific sliding speed is mereased owing to mereasing atomie disorder. With face-centred cubic metals the slidmg planes are of greater symmetry, and hence the static and impact curves are paralleł to one another.—A. R. P.

*Impact Torsion Tests (No. 3). I.— Coefficients of Viscosity of Solid Metals, n . Impact Torsion Tests of Cold-Worked Metals. Mititosi Itihara (Tech.r l L l h 512“516> 516-525; and (in Japanese)Trans. Soc. Mech. Eng. Japan, 1935, 1, 27-31).—[In English.l (I.— The apparent coefficients of viscosity (f*) of metals have been obtained from A t 5™erenoe j?etween the moments in the impact and static torsion tests.b™« ^ 7 ST • S in kg--sec-/om.2 has the following values :brass 5-27, aluminium 3-28, zme 2-55, copper 1-90, lead 0-06, Duralumin 0 .3J®™he8,for s,teels are higher. ( I I .- ) The impact diagrams of cold-worked and aged copper and brass show higher yield-points than those of the annealed metals to an extent wnich depends on the degree of ageins —A R P <? r H artaess Testing of Light Metals and Alloys. R. L. Templin (Amer. Soc. Test. Mat. Preprint 1935, 1-15).—One of the most used tests in the commercial mspection of metals is the hardness test, of one form or another. The success attamed in applymg the hardness tests to ferrous metal products has qmte naturaHy suggested similar uses for non-ferrous products. A critical

v ew of the factors afieetmg the more common hardness tests, however, reveals effects of different magmtude m some important instances, which wouldfnr rSl T Uu y the satisfa°t°ry ™e of the hardness tests

^ i? , 6, Presence of tŁe oxide films on aluminiumfZ Z l ’ ™ alloys coated Wlth relatively thin ]ayers Qf other different alloys are examples of the more conspicuous difficulties. The effects of other n rp lT ’ r af load7Penetration- time relationships, anvil or support, size and E I T . °i SpTCCl,t,en> are, *luantitatively quite different from those for ferrous metals. Likewise the relationships between difierent kinds of

+.7 e,®n 5lai'( n^ss and the other static properties of the light ntitatively ,different from those obtained in ferrous metals.

of rommerpin 1 l • application of the hardness tests to generał classesof commercial light-alloy products is discussed.—S. G.^ethod Machinę for Dynamic Hardness Testing [Ballentine Hard-

ness Tester]. W. M. Patterson(Amer. Soc. Test. Mat. Preprint, 1935, June,n h W a lW = mfS °u t1the, ne?d for,a reliable hardness scalę with definite physical umts of eąual yalue throughout the scalę, and comments briefly onA n IT ™ °i? ’ S1Y1I18 rcasons for the inadeąuacy of past methods.m p n t n f . s T ka^ness testing is described, and the develop-ment of a scalę fulfilling the desired conditions is explained. Test data are

356 Metallurgical Abstracłs V o l . 2

1935 X I I I .— Foundry Practice and Appliances 357given for alloys of lead, copper, and aluminium, cast iron and soft and medium- hard steels. The reproducibility of results to be expected with the method in laboratory and production work is estimated, and a brief discussion is given of the advantages and particular field of use of the machinę.—S. G.

A Method of Hardness Testing of Materials. Manabu Nakano (./. Soc. Mech. Eng. Tokyo, 1933, 36, (193), 322-325).—[In Japanese.]—S. G.

*The Thermal Conductivity of Metals in the Form of Smali Bars. Aurel Potop (Gompt. rend., 1935, 200, 1733-1735).—The thermal conductivity of smali bars can be determined (cf. Compt. rend., 1934,198, 1847) by the energy dissipated by a smali furnace in an enclosed space, when it is traversed by the bar which radiates the heat taken from the furnace. There are 2 difficulties in carrying out this method : (1) the coeff. of thermal exchange between the bar and the furnace is not very well defined; (2) when the bar is rather long (as is necessary for good conductors), it reąuires very careful centering. These 2 difficulties render void the underlying theory of the method which essentially presumes that the coeff. of exchange of the bar is constant at all points. To obviate these difficulties the furnace was rigidly fixed in the chamber in the correct position, and the diameter of the space in which the bar radiated was slightly increased. P. Yernotte has shown (■/. Physiąue, 1933, 4, 7, and Sci. et Ind., 1933, Nos. 228-OQQ\ ł t , 4- TCjD J 1 1 1 U, / 4 \th a t: + m ( j - 7)j , where Q is the heat dissipated by a bar of diameter, D, for a temperature difference, T, between the furnace and the surrounding space, H the coeff. of exchange between the furnace and the bar, and h that between the space and the bar, k the coeff. of conductivity,_ and X are the lengths of the bar and its seating in the furnace, respectively, and yj is a parameter defining the position of the bar. Hence Q is an inverse linear function of r„ and this has been verified experimentally with a bar of silver containing 10% of copper, 4 mm. in diameter and 117 mm. long. The value of k was found to be 0-82 eal. cm r1 degr1 sec.-1 as opposed to 0-84 found by older methods.—J. H. W.

X II.— TEM PE R A T U R E M EASUREM ENT A N D CONTROL(Continued from pp. 306-307.)

Indicating Pyrometers. M. D. Pugh (Met. Ind. (Lond.), 1935, 46, 647- 649).—A brief description is given of the use of indicating pyrometers in yarious metallurgical operations.—J. H. W.

Triple Rangę Optical Pyrometer. ------(Blast Fur. and Steel Plant, 1935,23, 280).—A brief note on the Pyro pyrometer with 3 scales : 1400°-2200° F (760°-1204° C.), 1800°-3400° F. (982°-1871° O.), and 2200°-3700° F. (1204°-2020° C.), the latter corrected for direct reading of true spout and pouring temperatures of molten metal in the open.—B. Gr.

X III.— FOUNDRY PRACTICE AND APPLIANCES(Continued from pp. 307-308.)

Some Factors which Influence Soundness in Non-Ferrous Castings. ArthurLogan (Found. Trade J., 1935, 52, 345-348, 367; discussion, 367-368).— Bead before the Scottish Branch of the Institute of British Foundrymen. The following are dealt with: present-day practice in casting brasses and bronzes ; excessive specifications; causes of unsoundness ; percentage waste ; defects due to the sand; melting; mould conditions; fluidity; cooling; controllable variables and the density of castings. In the discussion some defects were ascribed to “ tired metal.”—J. H. W.

Eliminating Surface Defects. B. V. Wallace (Blast Fur. and Steel Plant,1935, 23, 251-252, 278-279).—Considers the defects arising from the method


of construction and use of ingot moulds in steel practice in particular, but the observations are applicable to non-ferrous practice.—R. Gr.

Difficulties and Their Eemedies in the Casting of Thin-Walled AluminiumC a p s .----- Rahn (Giesserei-Praxis, 1935, 56, 13-14).—The precautions to beobserved in making the cores and moulds, and in melting aluminium for thin- walled castings are given.—J. H. W.

Difficulties in the Manufacture of “ Aluminium -Bronze ” Castings. M. Schied (Giesserei-Praxis, 1935, 56, 73-76).—The difficulties connected with making “ aluminium-bronze ” castings containing 90 : 10 copper-aluminium, w ith or w ithout up to 12% (total) of iron, nickel, manganese, Silicon, and tin are described, as to the use of pure materiał, making up the pre-alloy, the composition of the charge, and mould manufacture.—J. H. W.

*Dense Bronze Castings. G. Somigli (Industria meccanica, 1935,1 7 ,115-125; C. Abs., 1935, 29, 3283).—The various factors which influence the density of a bronze casting were studied experimentally. Moulding methods, shape of mould, composition of alloy, starting materiał, melting procedure, and temperature of pouring were investigated, and the microstructures compared. The best casting temperature is 1090°-1100° C. The numerous tests are described. A bibliography of 21 references is given.—S. G.

The Manufacture of Marinę Propellers. L. M. Atkins (J . Amer. Soc. Naval Eng., 1935, 47, 229-240).—The operations used in the manufacture of a high- tensile bronze propeller, including the preparation and assembling of the pattern, the method of moulding, the drying of the mould first for 24 hrs. at 150° C., then for 48 hrs. at 205° C., and finally at 230° C. until dry, the preparation and melting of the metal, the procedure of casting, the cooling for approximately 7 days, and the finał machining are dealt with in detail.

—J. W. D.Die-Casting of Brass. John R. Freeman, Jr. (Metals Technology, 1935,

2, A.I.M.M.E. Tech. Publ. No. 615, 1-7).—Describes briefly the Pack and Polak die-casting machines, with special reference to their use with brass. Results of tensile and impact tests on brass die-castings are given. When compared with the standard sand-casting alloys, the die-cast brass alloys in generał show superior tensile strength, but lower elongation values. Brass die-castings made properly in Pack and Polak machines are practically free from visual interna! cavities, but contain microscopic blowholes and shrinkage cayities, and have not the inherent soundness of forged metal.—W. H.-R.

X V — FURNACES AND FUELS


|T h e Bright-Annealing of Non-Ferrous Metals. W. Wirt Young (Gas Age- Becord, 1935, 75, 409—111, 414).—Plant and processes for the bright-annealing of non-ferrous metals by means of gaseous products of town’s gas after cracking or after combustion and purification are discussed and illustrated.—J. 8 . G. T.

The Bright-Annealing of Metals. Verdon O. Cutts (G.E.C. Journal, 1934, 5, 145-149).—Deals mainly with batch-type bright-annealing furnaces, particular reference being made to the Griinewald furnace, the feature of which is that it can be used for the bright-annealing of ferrous and non-ferrous metals without the use of a special atmosphere.—S. V. W.

Use of Electric Furnaces in Industrial Heat-Treatment.—III. A. Glynne Lobley (Metallurgia, 1935, 12, 9-13).—See Met. Abs., this volume, pp. 114, 180. A review of the adyances made in furnaces for bright-annealing and clean-hardening. Bright-annealing furnaces described are bell-type and water- sealed furnaces for batch-annealing, and wire-mesh belt-conveyor, roller- hearth, smali semi-continuous, and yertical continuous furnaces for continuous annealing. Consideration is also given to special gases for bright-annealing.

—J. W. D.

1935 X V I .— Refractories and Furnace Materials 359Special Atmospheres in the Heat-Treatment and Brazing of Metals. C. L.

West (Iron Age, 1935, 135, (20), 18-22, 86).—The use of “ Elfurno ” gases, instead of hydrogen or other strongly reducing gases, as an atmosphere in heat-treatment and brazing furnaces is cheaper and provides more flexible control. The “ Elfurno ” gas atmosphere is produced by simple combustion of carbonaeeous gases with suitable ąuantities of air in a special gas-producer at properly controlled temperatures. When practically all the oxygen from the atmospheric gas is eliminated, excessive amounts of hydrogen and other reducing components are unnecessary, thus reducing the cost of the gas.

—J. H. W.The Reactance of Large Rectangular Three-Phase Electric Furnaces. F. V.

Andreae (Electrochem. Soc. Preprint, 1935, Mar., 175-191).—Mathematical. Tables and formulse are given for rapidly determining the reactance of large furnaces and their other characteristics.—A. R. P.

*0n the Fundamental Eguations for the Design of Electric Resistance Furnaces. Kóichiró Maekawa (J. Inst. Elect. Eng. Ja-pan, 1933, (543), 873-881; Jap. J. Eng. Abs., 1935,13, 34).—[In Japanese, with English abstract]. From careful experiments, M. obtained a practical design formuła for electric resistance furnaces as follows : y — aa0-41; a = 0-0017jT1-55, where y is expressed in watts, x is the volume of the furnace in cm.3, and T is the temperature in ° C. The applioability of this formuła was verified in the design of two electric resistance furnaces for industrial purposes.—S. G.

High-Temperature Insulation for Industrial Furnaces. N. Allen Humphrey (Blast Fur. and Steel Plant, 1934, 22, 703-704, 712; 1935, 23, 85-87, 134-135, 141, 198-199, 212-214, 267-268).—Deals with calculations of fundamentals of high-temperature insulation.—R. Gr.

Developments in the Electrical Industry During 1934. John Liston (Gen. Elect. Rev., 1935, 38, 5-62).—In this generał review the following are of interest to non-ferrous metallurgists: continuous controlled-atmosphereelectric furnace for bright-annealing copper tubing in coils and straight lengths: furnaces for bright-annealing nickel-silver blanks and the continuous hydrogen-brazing of steel assemblies, deyelopments in the use of pressed metal powders, oxygen-free copper, and beryllium alloys.—S. V. W.

XVI.— REFRACTORIES AND FURNACE MATERIALS

(Oontinued from p. 309.)

Refractories in the Foundry. H. C. Biggs (Found. Trade J ., 1935, 52, 351- 352, 354).—Read before the Edinburgh Section of the Institute of British Foundrymen. A description is given of the composition and use of fireclays, their service behaviour, spalling slag attack, working conditions, rammed and brick linings, bonding materials, and the diflerent requirements of yarious portions of the furnace lining.—J. H. W.

*A Method for Decreasing the Porosity of Melting Tubes Made of Alumina. Tomo-o Sató (Tech. Rep. Tóhoku Imp. Univ., 1935,11,608-619).—[In English.] The porosity of alumina crucibles for use in the Tammann carbon resistance furnace is decreased by repeatedly soaking them in solutions of aluminium salts and heating between successive soakings to a temperature above the decomposition point of the salt.—A. R. P.

Characteristics of Some Special Refractory Products. Marcel Lepingle (Ind. chim.. Belge, 1934, [ii], 5, 393-403, 443-449).—The composition, melting point, resistance to compression, density, and porosity of numerous commercial grades of aluminosilicate bricks are tabulated and briefly discussed.—A. R. P.

Reduction of the Porosity of Normal Firebricks. ----- Beninga (Tonind.Z., 1934, 58, 651-652).—Very dense firebricks are obtained by using less than

360 Metallurgical Abstracts Vol. 28% of bmding clay with the grog; proyided that the latter is suitably graded howeyer, a reduction m the clay content is unnecessary.—B. BI.

Reduction in the Porosity of Normal Fireclay Bricks. A. Moser (Tonind. Z., 1935, 58, 779-781, 1260-1262).—A method is described for the manu- tacture of dense bricks with any desired ratio of grog and clay._B. BI,rp ,, EJ iu 1ci° ? Normal Fireclay Bricks. ------ Beninga[Tonind. Z., 1935, 58, 1047).—A critical contribution to Moser’s paper (cf. preceding abstract).—B. BI. 1 1 K

X V III— WORKING

(Oontinued from pp. 309-311.)

i n 9? d9(nreSS4Dg and D“ g‘ ----- (Metallurgist (Suppt. to Engineer), 1935,W, 24-26).—A review of the papers presented at the joint discussion on the subject held by yarious technical societies in London (and to be published in Proc. Inst. Automobile Eng.).—R. G.

The Effect of Roli Diameter in the Rolling of Sheets. W. Trinks (BlnM Fur. and Steel Plant, 1935, 23, 415, 430).—Discusses briefly the relation of roli diameter to the amount of “ crown ” produced on a sheet. I t is stated that, generally, m rolling heavy packs of sheets increase of roli diameter reduces „crown but in rolling thin packs, increase of roli diameter increases

crown. —Jtv. (jrr.Maintenance of Roli Neck Bearings. A. H. Frauenthal (Blast Fur. and

Steel Plant, 1935, 2 3 ,329, 330, 340-341).—Discusses deflection of roli necks and the design of bearings to cope with this effect.—R. Gr.

Eyolution in Seamless Tube Manufacture. Gilbert Evans (Met. Ind. (Lond.), 1935, 46, 555-556).—See also Met. Abs., this yolume p 74 The eyolution of seamless tube manufacture from the Mannesmann’ cróss-roll piercmg process of 1887 is briefly reyiewed.—J. H. W.

Development in Manufacture of Seamless Tubes. Gilbert Evans (Metal- lurgia, 1935, 12, 27-28, 34).— See also Met. Abs., this yolume, p . 74. The latest American deyelopments in the reduction of diameters and wall-thickness of tubes is discussed. A description is given of the recently-developed 1 oren rollmg-mill process, which is based on the principle of “ kneadins ” the materiał or subjccting the metal to pressure between solid surfaces at different points. A comparison is made of the output and properties of the product of this process with the Pilger process. The generał arrangement of the recently-developed Diescher process, which is used for non-ferrous tube manufacture in the U.S.A. is also given.—J. W. D.

in, Latin, Li terature from Antiąmty to Renaissance. Wilhelm Theobald (Glasers Ann., 1934, 115, 57-59).—Historical survey.—B. BI.i KQ?Plnr!?iln8 Shee.t ,MetaIs- w - B- Francis (Met. Ind. (N.Y.), 1935, 33, 155-described —A mR Pp S modern *°ols and methods of spinning metals are

X I X — CLEANING AND FINISHING


Recent Adyances in Metal Cleaning Technology. R. W. Mitchell (Metal Cleaning and Fmishing, 1935,7,9-14, 65-68; G. Abs., 1935,29,3275).—A brief description of some of the more important recent deyelopments. The nhysical properties are giyen of the foHowing recently adopted cleaning solyents:T i.1 %12’ hy}en,e, trlclllorethylene, propylene dichloride, ethylenedichlonde, and CC14, and the corrosion of copper, steel, brass, and KA2S in

ln »■! ».lpŁo„W

1935 X I X .—'Cleaning and Finishing 361Cleaning Metals Jor Plating. D. W. Bobinson (Monthly Rev. Amer.

Electroplaters' Soc., 1935, 22, (5), 32-36).—Gives some practical hints on cleaning metals in hot alkaline baths and in electric cleaners, together with the compositions of suitable baths for various purposes.—A. B. P.

Electrochemical Interpretation of Pickling Processes. E. Jimeno and I. Grifoll (Anales soc. espan. fis. quim., 1934, 32, 1135-1141; O. Abs., 1935, 29, 3240).—A discussion of the reactions involved.—S. G.

tM etal Colouring with Molybdate Solutions. H. Krause (Miłt. Forschungs- inst. Edelmetalle, 1935, 8, 138-143).—Zinc can be coloured yarious shades of brown to blaek by immersion in an oxalic acid solution of ammonium molybdate, and tin, lead, and cadmium by immersion in molybdate solutions containing sodium fluoride or silicofluoride. Black tones on zinc and aluminium are obtained in thiosulphate-molybdate baths or in sodium acetate-ammonium molybdate baths. The effects of varying the concentration of the bath and the time of immersion on the colours of the fiłms produced on aluminium and zinc are deseribed, and recent patent literature on the subject is reviewed.

—A. B. P.Colouring Aluminium Brown, Black, and Grey. H . Krause (Aluminium,

1935, 17, 259-260).—Aluminium may be coloured brown by pickling in a hot solution containing potassium permanganate 5-10 grm., copper nitrate 5 grm., and nitric acid (d 1-35) 2—1 c.c. per litre. A light brown colour is obtained in 5 minutes and a velvet brown in 10-15 minutes; to obtain a black colour the copper nitrate content is raised to 20-25 grm./litre and the time of immersion to 30 minutes. A matt grey colour is obtained with a piekle containing diammonium hydrogen phosphate 100 and manganese nitrate 5 grm./litre.

—A. B. P.*Rapid Electrolytic Patina on Copper. G. L. Craig and C. E. Irion (Metals

and Alloys, 1935, 6, 35-37).—When a clean copper sheet is made the anodę in a solution of sodium carbonate or, preferably, bicarbonate (e.g. an 8% solution) and a current of 15 amp./dm.2 is passed from it to an iron cathode, a beautiful green patina is formed in 1 minutę. The coating consists essentially of a basie carbonate (malachite), is very adherent, and does not flake on bending or by temperature changes between + 50° and — 23° C.; on prolonged exposure to the atmosphere it is converted into the basie sulphate, brochantite, without change of colour or structure, the atmospheric sulphur trioxide simply replacing the carbon dioxide. The patina may bo produced in situ on old or new structures provided any oxide is first remoyed by a sulphuric acid wash, followed by a water spray; an iron roller eovered with a felt pad impregnated with the solution is then passed over the copper while the correct current is passed between the two.—A. B. P.

Lacąuering Metallic Articles. Erik Hallstróm (Industritidning. Norden,1934, 62, 188-189).—A reyiew.—S. G.

*Finishing and Frictional Resistance of Bearing Metal (A New Apparatus Devised for Finishing the Metal Surface). Motomu Ishida (Buli. Research Office Jap. Oovt. Railways, Tokyo, 1933, 21, (25), 1 ^7 ; Jap. J. Eng. Abs., 1935, 13,13).—[In Japanese.] I. gives some details of the flnished surface of bearing metals and their practical value as determined by friction tests on the surfaces of the metals flnished by various methods, and from measurements of their frictional resistance and inerease in temperature. Further, he proposes the use of a new finishing device for obtaining the best surface for bearing metals.

—S. G.*A Study on the Manufacture of Tools. II.—Investigation on the Abrasive

Action of Grinding W heels. Yaekiti Sekiguti and Itiro Hasegawa (J. Soc. Mech. Eng. Tokyo, 1933, 36, (198), 700-710).—[In Japanese.]—S. G.

Grinding and Polishing of Aluminium and Its Alloys. [A.] von Zeerleder (Aluminium, 1935, 17, 245-251).-—Apparatus for grinding and polishing alu


minium and its alloys is described, and recipes are given for suitable polish- ^ e^ a* -A- table showing the mechanical properties of numerous commer

cial light alloys in yarious stages of heat-treatment, and many photographs of aluminium alloy surfaces after yarious polishing processes are included.

__A R . po°f ^ ec ro^eP°s^s of Cadmium. F. Schwarz (Oberflachentechnilc,

u 9 &")•— T h e usual cadmium deposits on steel are so soft that evenbuffing with Vienna lime will produce perforations. I t is recommended to harden the deposit by adding zinc to the bath so as to deposit an alloy of 85% cadmium and 15% zinc. This alloy is deposited at a current density of 20- 40 amp./ft.2 from a bath containing equal ąuantities of zinc and cadmium; it can be buffed with a pastę of Vienna lime 12, tallow 2, stearin 2, Montan wax 1, and minerał oil 1 part.—A. R. P.

X X .— JOINING


New Metal to Glass Seal. ----- (Amer. Metal Marlcet, 1934, 40, (185), 7,brief no te. Tight and reliable joints can be made between glass and

the alloy J ernico and may be used in vacuum tubes and parts when gas-tight insulating seals are reąuired. Femico can be machined, forged, punched, drawn, stamped, soldered, copper-brazed, and welded. Its composition is not given.—I. M.

Hard Soldering with the Blowpipe. ------- (Oxy-Acetylene T ips, 1935, 14,® The properties of silver solders are described, and recommendationsfor their application by the oxy-acetylene blowpipe are given—clean, close joints, borax flux, and a soft flame applied to the work only and never to the wire or the solder in the joint. Large copper process vessels with silver- soldered joints are illustrated.—H. W. G. H.

Atmospheres in the Heat-Treatment and Brazing of Metals.(West.)—See p. 362.

*0n the Problem of Welding Aluminium. Stephan Haarich {Z.V.d.I.,1935, 79, 495-499).—The results of comparative tests on the effect of different methods of welding aluminium on its gas content, structure, mechanical properties, and resistance to corrosion are described. Electrical welding methods are satisfactory. The gas content of the weld metal is greater than that of the basis metal in all processes. The hardness, tensile strength, and yield- point all decrease, while the elongation increases with increase in size of the welding flame. Hammering of the weld decreases its resistance to corrosion.

_gRepairing Faulty Aluminium Castings. Edmund R. Thews (Giesserei-

Praxis, 1935, 56, 119—121).-—The precautions to be observed in repairing aluminium castings by welding are given. Particular care must be taken to clea,n carefully and to preheat the parts to be welded, and to allow them to cool slowly. The process of welding aluminium is described in some detail.

, —J. H. W.Aluminium Alloy Crankcases. ----- (Soudeur-Coupeur, 1935, 14, (3), .16-

20). -Recommendations are given for repairing broken crank-cases by oxy- acetylene welding, and typical repairs are illustrated, with particulars of welding times and gas consumptions.—H. W. G. H.

Some Fundamentals of Spot-Welding, Especially of the Light Alloys. R. H. Hobrock (Metals and Alloys, 1935, 6, 19—25, 41—45, 67—69; and (summary) Light Metals Re,v., 1935, 1, 403—407).—In spot-welding, union ofthe parts m contact occurs chiefly by recrystallization of the metal just below the melting point. Although a smali amount of looal melting usually

1935 X X .— Joining 363occurs, care should be taken to avoid this spreading, otherwise a hole is liable to be formed, especially in thin sheets, owing to the aetion of the eleetrical forces on the molten metal. In metal which is to be age-hardened, melting should be avoided sińce it develops a local “ casting ” structure which is unsatisfactory for subseąuent heat-treatment. The pressure between the electrodes of the welding machinę is usually sufficient to break down the surface oxide film without cold-working the metal and, when the current is sufficiently great, to cause the desired recrystallization. Nevertheless, better welds are obtained with highly polished surfaces as these have a lower resistance, and thus local burning is more easily avoided. The best type of electrode is that which gives even distribution of stress, i.e. that which terminates in a cone the angle of generation of which is equal to the angle of friction (about 7°).—A. R. P.

The Process o! Electric Spot-Welding : Its Application to Stainless Steels and Light Alloys. G. Mandran (Aciers speciau.r, 1934, 9, 636-680).—In Part I (19 pp.), the generał principles and chief applications of electric spot-welding, and the machines used in the process are described; in Part II (20 pp.) the application of this process to the welding of 18:8 stainless steel is explained; while in Part III (6 pp.) the applications of the process to the spot-welding of aluminium and light alloys (such as Duralumin) are explained.—J. H. W.

* Welding of Staybolts in the Coper Firebox Walls of Locomotive Boilers.■-----Cramer (Glasers Ann., 1934, 115, 89-90).—After an investigation of thecauses of ring-shaped corrosion areas around the heads of the staybolts, a method is described for welding these bolts into the walls of the boxes so as to ayoid unsound places between them and to obtain a smooth firebox wali.

—B. BI.The Welding of Joints in Copper Pipes for Water and Sanitary Installations.

W. L. Kilburn and E. B. Partington (Welding Ind., 1935, 3, 96-100; discussion, 158-160; and (abstract) Welding J ., 1935, 32, 102).—The advantages of copper in plumbers’ work, and of bronze-welding as a method of jointing, are explained. Typical joints are illustrated and the technique reąuired to make them is described. I t is stated that no trouble need be feared from electrolytic corrosion. When welding copper to brass fittings, it is pointed out, an oxidizing flame should be used.—H. W. G. H.

Bronze Joints for Copper. ----- (Oxy-Acetylene Tips, 1935, 14, 53-55).—The fabrication of process piping for a paper mili by bronze-welding is described. I t is stated that a bronze-welded joint is not attacked by sulphurous acid or sulphur dioxide any more readily than copper, and that the electrolytic effect produced by two dissimilar metals in mechanical contact is practically absent when they are fused together.—H. W. G. H.

Lead Welding. ----- Korta (Anz. Masch., 1935, 57, (42), 4-5).—Lead isbest welded with the oxy-hydrogen flame. Although the acetylene, coal-gas, and petrol blow-lamp flames can also be used, their use is scientifically unsound. A new type of welding torch is described, and the shape of the individual welds is discussed in detail.—B. BI.

Lead-Welding with the Oxy-Acetylene Flame. F. Schulze and Johs. Staebler (Autogene Metallbearbeitung, 1935, 28, 68-70).—The use of a smali oxy-acetylene blowpipe is recommended instead of the older oxy-liydrogen burners. This should preferably be of the high-pressure type, as flame eontrol is important. Welders, unaccustomed to working with lead, are apt to have difficulty at first on account of its low melting point, but there are no real difficulties in techniąue.—II. W. G. H.

*0n a Change of Method of Welding-On Hard Alloys on to Drills. G. Var- shavski (Azerbaidjanskoe Neftianoe Khoziastvo (Oil Economy of Azerbaidjan), 1934, 14, (1), 81-83).—[In Russian.] Tests of oil-boring drills with welded-on alloys—the harder Pobedit along the edge and for J from the periphery and

the sof ter Wokar for f from centre to periphery—showed that wear takes place almost entirely along the horizontal piane.—D. N. S.

*Laboratory Experiments of Welding-On Hard Alloys by Alternating Current.P. M. Rostomian (Azerbaidjanshoe Neftianoe Khoziastuo (Oil Eam om y of Azerbaidjan), 1934, 14, (9), 47-54).—[In Russian.] Increasing the current in the welding of Wokar (hard alloy) on to boring drills decreases the resistance to wear. The ratios of resistance and homogeneity of welding obtained with d.c. to those with a.c. a re : resistance to wear, 1: 1, 0*75 : 1; homogeneity, 1 : 1-87, 1 : 2-33; current, 100, 200 amp., respectively.—D. N. S.

*Testing Various Methods of Welding-On “ Wokar ” Alloy. N. A. Var- tanessov and E. V. Chemysheya (Azerbaidjanshoe Neftianoe Khoziastvo (Oil Economy of Azerbaidjan), 1934,14, (10), 52-54).—[In Russian.] “ Fish-tail ” shaped oil-boring drills were tested, in ordinary working conditions, with Wokar hard alloy welded-on by the foliowing methods : (1) ordinary welding - on in 3 layers by a.c.; (2) the same with d.c.; (3) welding-on in strips; (4) the same, but with strengthening of the edges with Pobedit hard alloy; (5) bi- lateral welding-on. Strip welding proved unsatisfactory, and the bi-lateral method has no advantages over methods (1) and (2) while using more hard alloy.—D. N. S.

Repairing Zinc-Base Die-Castings by Oxy-Acetylene Welding. C. W.Mace (Welding Ind., 1935, 3, 79-84; and Met. Ind . (Lond.), 1935, 46, 477- 479, 528-529).—The welding rod should be of similar composition to the casting with slight excess of zinc. The joint should be veed for thicknesses of in. or over and carefully cleaned, any electroplating being removed from the vicinity. The flame must be adjusted to have a slight excess of oxygen whilst remaining “ soft.” Puddling of the rod into the molten casting is essential. The remainder of the techniąue is very similar to that used for aluminium alloy castings. Welds of 100% strength should be obtained.

—H. W. G. H.Welding as Applied to Vehicular Structures. Stanley E. Evans (Welding

J ., 1935, 32, 106-108, 123).—Design for economizing in weight is discussed and brief notes on the welding of mild and alloy steels, copper, aluminium, and its alloys are given.—H. W. G. H.

Application of Electric Welding in Locomotive and Car Repair Shops. Kaniti Yamaguti (J. Soc. Mech. Eng. ToJcyo, 1933, 36, (195), 472^76; Jap. J . Eng. Abs., 1935,13,9).—[In Japanese.] Recent electric welding operations at the Oi Locomotive and Car Repair Shop, and electric welding in generał, are described.—S. G.

Recent Developments Regarding Welded Joints and the Effects of Fatigue.O. Bondy (Welding Ind ., 1935, 3, 60-64; discussion, 101-104; and (abstract) Welding J ., 32, 70-71).—The present point of view in Germany regarding the fatigue testing of welded joints and their use in fatigue conditions is reviewed.

—H. W. G. H.Shrinkage Strains and Stresses Caused by Welding. Riddervold Jensen

(Welding Eng., 1935, 20, (2), 30-36; (3), 21-23).—Ten rules for minimizing shrinkage stresses and strains are enunciated and enlarged upon. The dangers of residual stress and shrinkage cracks are discussed.—H. W. G. H.

Some Explosion Experiments with Liquid Acetylene. Alwin Krausz (Autogene Metallbearbeitung, 1935, 28, 72-74).—It was found that liquid acetylene resisted attempts a t ignition by an incandescent wire when the gaseous phase was explosive under the same conditions of temperature and pressure.

—H. W. G. H.

364 Metallurgical Abstrads V o l. 2, 1935

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